Arena

A video explaining the Arena in Hearthstone made by the Curse Gamepedia YouTube Channel.

The Arena is a game mode where players compete against each other using specially constructed decks to earn substantial rewards. It features strong elements of luck and chance, with players essentially gambling upon their own success to try to earn rewards by winning as many games as possible before their deck is knocked out. Each admission to the Arena costs either 150 in-game gold or real money equivalent to $1.99 USD, €1.99 EUR, £1.99 GBP, R$4.50 BRL, or ￥12.00 CNY.

Upon entering the Arena, the player will be allowed to select one of three randomly selected classes. They can then choose from a series of randomly selected cards to build a new, unique deck. Unlike other play modes these cards are not limited by the player's current collection, and there is no limit on the number of each card that can be included in a deck (including legendaries). Players then use their decks to do battle until they have suffered 3 losses, or claimed 12 victories, at which point they will be granted a number of rewards depending on their success. Winning at least 7 games before being eliminated guarantees that the player will earn their entry fee back in gold. Players do not have to play all of their Arena games in one go, and can return to continue their run whenever they wish.

With its random selection of heroes, the Arena is locked for players until they have unlocked every class.

Getting started

Choosing a class

Choosing cards

After paying the entry fee, the player will be presented with three random hero classes to choose from. Once a hero has been selected, they will then be shown thirty different sets of cards, each set featuring three different cards. The player must select one card from each set to be included in their new Arena deck; the two cards not chosen from a set are effectively discarded. Once a card has been chosen, the player cannot undo their selection.

Unlike in constructed play, where each deck can feature a maximum of 2 of each card (and 1 of each legendary), there is no limit in Arena decks to the number of each card that may be featured. Some cards, especially those of lower rarity, may appear several times in different selection sets. All cards featured in a selection set will be of the same rarity. For example, sets may offer three common cards, or three legendary cards. It should also be noted that only neutral cards and cards for the selected class will be offered. As the player picks cards, the current decklist is shown on the right of the screen, and the deck's mana curve is displayed at the bottom of the screen, serving to give a quick indication of how the deck is balanced. Once the deck is complete, clicking the "Play" button will queue the player up for a battle against another Arena player.

Deck construction in Arena differs from that in other types of play; while the player is still able to construct a deck before doing battle, in Arena the final deck is as much the result of luck as it is careful strategy. Players have no way of knowing which cards will be offered next, making each choice difficult to make. Additionally, the fact that each card may appear several times through the selection process alters the normal rules of the game and makes weighing each card's value against that of another a slightly different process. Players with a specific strategy in mind can only hope that cards fitting to that strategy will be selected for them; or else must bend their strategy to fit the cards on offer. Because they feature randomly selected cards, Arena decks also largely transcend any involvement of real money expenditure in their construction, placing players on a relatively even playing field.

Card selection

NB: Following Patch 7.1.0.17720 in February 2017, the rules for Arena card drafting have changed substantially. All official arena-specific rules are found on various official webpages, with the main ones here: the official Battle.net Arena-specific forum post and the most recent Patch 10.4 blog post.

NB: Following Patch_12.0.0.25770 in August 2018, Blizzard publicly released an official Arena card buckets list and along with it a file containing simulated appearance rates. Please see the Patch 12.0 Arena update blog post.

The drafting process consists of thirty 'picks', where the player is presented with three possible cards to choose from. All cards in a given pick will be of the same rarity, but may be class cards or neutral, and of any card type. Multi-class cards may be included if they match the player's class.

Arena uses Standard format, including only cards from expansions and adventures currently included in the format; for a list, see Standard format#Standard card sets.

Card buckets

Please add any available information to this section.

Arena uses card buckets to determine which cards are shown to the player during the drafting process.

Refer to the official list of card buckets made public by Blizzard:

• card_buckets.csv - August 1, 2018

Card appearance rates

Each card in Arena has its own chance of appearing in draft picks.

Refer to the raw datafile generated internally by Blizzard using 100,000 Arena draft simulations for card appearance rates:

• appearance_rates.csv - August 1, 2018

General rules

A number of factors affect the likelihood of a given card being presented for selection:

• Only cards from Standard format will be included in picks.
• On average, the rarity of Arena cards show up as 60% Common, 28% Rare, 10% Epic, and 2% Legendary.
• Spells have an increased chance to appear.
• Weapons have an increased chance to appear.
• Neutral cards from the Classic set have a reduced chance to appear.
• Class-specific cards are given "a huge boost" in likelihood of appearing, in order to balance the far larger number of neutral cards.
• Cards from the latest expansion or adventure are more likely to appear, at least for a while after the release of the related content. For example, during January 2016 cards from The League of Explorers were given an additional 50% likelihood of appearing. The duration of this boost appears to end prior to the next content release, with One Night in Karazhan seeing an increase from August 11 to October 20.
• Certain specific cards (see below) are also excluded or have reduced chances of appearing.

These factors aside, card selection is otherwise random, and is not affected by previous card selections, runs or synergies.

No longer apply

• As of Patch 9.0.0.20457, the first two sets of cards in a draft are more likely to include synergy-based cards.
• 26 of the 30 picks choose a rarity according to the follow odds: 68% Common/Free, 20% Rare, 9% Epic, 3% Legendary.
  • The remaining 4 picks are 'Rare' picks that have a chance to be upgraded to Epic or Legendary at a slightly higher rate.
  • Any individual common card should show up about as often as any individual rare card.

Specific cards

Reduced chance

The following cards have a reduced likelihood of appearing in draft picks, on top of the other factors listed above.

Category	Cards	Reduction
Mage	Flamestrike	50%
Warlock	Abyssal Enforcer	50%

Exclusions

The following cards are excluded from the Standard format card pool and will not be offered as draft picks during the Arena selection process. However, random effects are not affected by exclusions and can still give most of these cards, with the exception of Quest cards which cannot be randomly obtained by any means.

Category	Cards
Druid	Savagery - Soul of the Forest - Mark of Nature - Jungle Giants - Malfurion the Pestilent - Gloom Stag
Hunter	Starving Buzzard - Timber Wolf - Snipe - The Marsh Queen - Deathstalker Rexxar
Mage	Open the Waygate - Frost Lich Jaina - Black Cat
Paladin	The Last Kaleidosaur - Uther of the Ebon Blade
Priest	Mind Blast - Lightwell - Inner Fire - Awaken the Makers - Shadowreaper Anduin - Glitter Moth
Rogue	The Caverns Below - Valeera the Hollow
Shaman	Dust Devil - Totemic Might - Ancestral Healing - Windspeaker - Unite the Murlocs - Thrall, Deathseer - Murkspark Eel - Hagatha the Witch
Warlock	Sacrificial Pact - Sense Demons - Succubus - Lakkari Sacrifice - Bloodreaver Gul'dan
Warrior	Warsong Commander - Charge - Rampage - Fire Plume's Heart - Scourgelord Garrosh
Neutral	Vicious Fledgling - Genn Greymane - Baku the Mooneater

Golden cards

Cards presented for selection may be golden or regular depending on the player's collection:

• If the player owns the maximum usable number of golden copies of a card (1 for legendaries, 2 for all other rarities), all copies of that card appearing in drafts will be golden.
• If the player owns 1 copy of a non-legendary card, the first copy of that card appearing in drafts will be golden; the others will be regular.
• If the player owns no golden copies of a card, all copies of that card appearing in drafts will be regular.

Playing Arena

Commencing an Arena run

Play in Arena consists of a series of matches between Arena players, with each player using their specially constructed deck.

During each Arena run the player can suffer up to three losses, with the number of losses so far displayed on the Arena screen. Once a player has lost 3 times, or won 12 times, their run will end, and rewards befitting their success (or lack thereof) will be offered. Once the run has ended, the player's deck will be destroyed, and cannot be viewed or played with again.

Players can also choose to retire their deck at any time and claim their reward. However, it should be noted that completing all of a deck's Arena matches cannot reduce the reward on offer, only improve it. Retiring a deck should therefore be a last resort used only when unwilling to play with the deck any longer.

It should also be noted that if either player is disconnected from the server during a match and fails to return through the reconnection feature, that match is counted as a loss for the disconnector.

Matchmaking

Matchmaking for each pairing is determined by the player's win/loss record for the current run, attempting to find a player with as similar a record as possible. Other factors such as class, deck and past Arena performance do not affect matchmaking.

New players

For players on their first few Arena runs, matchmaking is intentionally altered to provide an easier transition into the game mode. For matchmaking purposes, the player's win/loss ratio is considered to have one more loss than it actually does, thus matching them against what should on average be easier opponents. The system will also prefer to match such players against each other.

The exact number of games required to be eligible for this adjustment is something that the developers are "still tweaking a little", but as of April 2016 is "in the realm of 2 or 3 runs." Once the player has exceeded this number of runs, they are matched purely on their win/loss ratio, with their number of previous runs no longer affecting their matchmaking.

Claiming rewards

The 13 possible Keys

Opening rewards

Claiming rewards

Once the player has won 12 games in total, lost 3 games, or retired their deck, they will be given a Key to open up the chest for their reward. Much like when opening a card pack, the player will be presented with a number of individual rewards, and must click on each in turn to discover their contents.

A range of rewards are possible, with both the number of individual rewards granted and their possible contents determined by the number of games the player has won. Rewards may consist of card packs, gold, Arcane Dust (used for crafting) and individual cards, including golden cards.

Reward structure

Each Key will grant the player a number of rewards, but the contents of each reward is determined randomly according to a range of possible values for that Key. Higher-level Keys grant a larger number of rewards, with more valuable contents. Higher-level Keys also have a range of possible values for the total number of rewards granted. The 12-win Key does not reward dust as a prize, instead providing other rewards.

Certain rewards are guaranteed for each Key. The remaining rewards are determined randomly from a number of possibilities. The type of each reward appears to be chosen individually from the range of possibilities, with the result that each possible reward may be granted multiple times by the same Key. For example, a Key may reward several individual portions of arcane dust, several individual cards, or a mix of the possible reward types.

All Keys grant the player one guaranteed card pack. Keys at higher levels also offer a guaranteed gold reward, of a larger amount than other possible gold rewards for that Key.

Ranges

• All gold and dust rewards have a range of possible values for each Key.
• Individual card rewards may be common, rare, epic, legendary and/or golden, and are not limited by class. Individual card rewards may be from either the Classic set, or any expansion set currently in Standard format. Higher rarities/golden versions of individual cards appear to be far more common at higher levels, but according to some reports can occasionally occur at lower levels. As of Patch 9.0.0.20457, non-golden common cards are no longer offered as a reward for runs with with three or more wins (previously all except the three highest keys could reward non-golden common cards).
• The guaranteed card pack given each run will always be from the most recently released expansion set. If the player earns a second card pack from the same run, they will always be from a different Standard format set.

Notes

Players will always be awarded one card pack regardless of the number of games they have won, and even losing 0-3 will also grant a small amount of gold/dust. Since card packs can be purchased directly from the shop for 100 gold, this essentially makes the additional cost of an Arena run 50 gold, minus however much additional gold or dust is rewarded - assuming the player desires cards from the latest expansion set. If the player can earn more than this amount back in additional rewards, the run can be considered to have been profitable. Being awarded a second card pack automatically makes the run profitable, even without considering other rewards. Gaining experience in playing Arena can of course also be considered a worthwhile reward, especially in the beginning.

Winning at least 7 games will earn the player their entry fee back in gold, in addition to other rewards. This is colloquially known as "going infinite" as the prize gold can be used directly to start another arena run, which could pay for another run at 7 wins, repeating infinitely. Winning 3 to 6 games will compensate for the difference between buying a pack directly and earning one through Arena.

The presence of different rewards can affect the size/quality of the other rewards selected for that player. For example, being awarded a common card will increase the value of the other rewards granted by that Key. This may be due to the likelihood of the player already owning or simply having no desire for any given common card, making it likely they will simply disenchant it, for a mere 5 Arcane Dust.

Rewards are based solely upon the number of wins for the current run, and are not affected by performance in previous runs.

Table

The below table aims to chart the range of possible rewards for each key. The 'No.' column lists the number of individual rewards granted by each Key.

This table represents a collective effort to chart the range of possible Arena rewards. The possible ranges of dust and gold rewards are presumed to be slightly larger than those stated, and individual cards are likely available at slightly lower levels than currently listed. Additionally, it is possible for higher rarity cards to be obtained at far lower levels than listed here, but the probability of this appears to be extremely low.

When adding data, please note individual rewards, e.g. 235 + 85 + 20 gold, rather than simply 340 gold.

Wins	Key	No.	Guaranteed rewards	Random reward pool
0	Novice	2	One card pack One random reward	25-40 gold 25-40 dust One common card
1	Apprentice	2	One card pack One random reward	30-50 gold 25-50 dust One common card One card pack
2	Journeyman	2	One card pack One random reward	35-60 gold 40-50 dust One common card One rare card One card pack
3	Copper	3	One card pack 25-35 gold One random reward	20-25 gold 10-25 dust One rare card One card pack
4	Silver	3	One card pack 40-60 gold One random reward	20-30 gold 10-25 dust One rare card One card pack
5	Gold	3	One card pack 45-60 gold One random reward	45-60 gold 45-60 dust One rare card One card pack
6	Platinum	3	One card pack 75-85 gold One random reward	45-60 gold 45-60 dust One rare card One card pack
7	Diamond	3	One card pack 150-160 gold One random reward	20-30 gold 10-25 dust One rare card One card pack
8	Champion	4	One card pack 150-160 gold Two random rewards	20-50 gold 15-25 dust One golden common card One golden or regular rare card One golden or regular epic card One golden or regular legendary card One card pack
9	Ruby	4	One card pack 150-165 gold Two random rewards	20-120 gold 10-50 dust One golden common card One golden or regular rare card One golden or regular epic card One golden or regular legendary card One card pack
10	Frostborn	4	One card pack 150-185 gold Two random rewards	65-125 gold 65-95 dust One golden common card One golden or regular rare card One golden or regular epic card One golden or regular legendary card One card pack
11	Molten	4	One card pack 195-210 gold Two random rewards	65-205 gold 60-95 dust One golden common card One golden or regular rare card One golden or regular epic card One golden or regular legendary card One card pack
12	Lightforge	5	One card pack 215-225 gold 25-35 gold Two random rewards	65-185 gold One golden common card One golden rare card One golden or regular epic card One golden or regular legendary card One card pack

Events

Occasionally, Blizzard will change Arena for a limited time, either by adding exclusive cards or modifying the drafting system.

Taverns of Time

For (Jun 11th~July 2nd, 2018), 28 new Arena-exclusive cards are able to be drafted, 2 for each class and 10 neutral cards. TODO:Add pages for remaining cards. TODO:check rarity for these cards, though gems are not shown.
Class Cards

Class	Card 1	Card 2
Druid	||
Hunter	||
Mage	||
Paladin	||
Priest	||
Rogue	||
Shaman	||
Warlock	||
Warrior	||

Neutral Cards

Non-Legendary (8 cards)

Legendary (2 cards)

Uncollectable

Wildfest

During Wildfest, Wild cards were able to be drafted.

Arena-exclusive cards

For (period of time), each class gained one Arena-exclusive card that was able to be drafted. The cards were chosen by the community from a vote between three class cards.

Class	Winning Card	Rejected cards
Druid	||
Hunter	||
Mage	||
Paladin	||
Priest	||
Rogue	|| Assassin's Training
Shaman	||
Warlock	||
Warrior	||

Double class

On (Halloween 2017), players were able to play as two classes at the same time. The first pick chose the Hero Power while the second pick adds that class's cards to the card pool.

Goblins vs. Gnomes sneak peek

Before the release of Goblins vs. Gnomes expansion, cards from the set were able to be drafted in Arena.

Strategy

The strategy in Arena is considerably different from constructed play. The emphasis in "draft" mode is on knowing the powerful basic cards and which classes have the best class-specific cards. Constructed, on the other hand, is much more reliant on the player's card pool and synergies between the cards they choose to play. Players may wish to make sure they have a good grounding in the game and the capabilities of each class before entering the Arena, as the admission charge can make Arena play costly for unsuccessful players.

There are two key differences between Arena and constructed play. Firstly, the deck is not limited to 2 of each card. This can allow players to build outlandish and otherwise impossible decks, such as a mage with 7 x Frost Nova, a priest with 5 x Northshire Cleric, or a warlock with 2 x Malygos. In regular play players can use this limit to anticipate their opponent's possible cards; for example, it can generally be trusted in regular play that a priest who has already played 2 x Mind Control has no more Mind Control cards in their deck. Arena offers no such certainty; a player may lack many key basic cards, or may feature several of the same card. This affects Arena play because players are far less able to anticipate the deck construction and play of their opponent.

Secondly, players must select their cards in a fairly random process. This typically results in relatively random and unpredictable decks, and has two consequences: firstly, players cannot necessarily use their opponent's known cards to deduce the style of the rest of their deck, as is possible in constructed play; and secondly, there is a strong advantage when constructing a deck to attempt to build a strategy that is versatile, easily formed from multiple possible cards, and can function well in spite of key cards being missing from the deck. Class-specific cards are also generally selected less commonly in Arena card sets than in constructed play, making strong synergy decks less likely to find success in Arena.

Rankings

At the end of each month the top 100 players in the Americas, Europe, and Asia regions are listed on the official site (for the corresponding region). Players are ranked by their average wins per run, with a minimum of 30 runs.

Statistics

Arena competition presents a very specific pattern of player elimination. As each player must either win or lose each game to proceed to the next match, it is possible to calculate the specific percentiles and distribution across the possible win/loss records. This allows players to mathematically rank their run in the Arena according to the percentage of players who have achieved the same record.

Note that these statistics do not represent the player's actual chances of reaching any number of wins. Success in Arena is substantially determined by deck construction and skill in playing each match. The numbers below merely reflect the proportion of players who reach each number of wins. In addition, while these numbers reflect the intended design, for reasons of shortening queue times it is possible players will not always be matched against players with precisely the same score. However, given the large player pools currently seen in-game, any deviation from the design is expected to be negligible.

Number of wins

Players may complete their Arena runs with between 0 and 12 wins, with the number of wins directly determining the scale of the prizes awarded.

The below table lists the percentage of runs that reach each number of wins. For example, Arena runs achieving 5 wins are in the top 22.66% of runs. 50% of Arena runs will achieve 3 wins or more.

Wins	Percentage
0	100.00%
1	87.50%
2	69.69%
3	50.00%
4	34.38%
5	22.66%
6	14.45%
7	8.98%
8	5.47%
9	3.27%
10	1.93%
11	1.12%
12	0.65%

Exact sequence of matches

Each Arena run features a potential of 14 matches for each player, with runs ended upon reaching 3 losses or 12 wins. In each match, it is possible to win or lose the game, dividing the players between one of two possible paths.

The below table shows the percent of runs that will reach each given point on the overall potential sequence of matches, with numbers rounded off to two decimal places. The numbers in bold indicate possible final scores, assuming the player does not retire their deck. For example, we can see that only 0.02% of runs end at 12-0, and that the most common score is either 1-3 or 2-3, with more than a third of all Arena runs ending with one of these scores.

	Lost
Won	0	1	2	3	Combined
0	100%	50%	25%	12.5%	12.5%
1	50%	50%	37.5%	18.75%	31.25%
2	25%	37.5%	37.5%	18.75%	50.0%
3	12.50%	25%	31.25%	15.63%	65.63%
4	6.25%	15.63%	23.44%	11.72%	77.34%
5	3.13%	9.38%	16.41%	8.20%	85.55%
6	1.56%	5.47%	10.94%	5.47%	91.02%
7	0.78%	3.13%	7.03%	3.52%	94.53%
8	0.39%	1.76%	4.39%	2.20%	96.73%
9	0.20%	0.98%	2.69%	1.34%	98.07%
10	0.10%	0.54%	1.61%	0.81%	98.88%
11	0.05%	0.29%	0.95%	0.48%	99.35%
12	0.02%	0.15%	0.48%	-	100.0%

2016 statistics

The global portion of the 2016 infographic

In October 2016, official statistics were released for Arena play between January and September 2016. A series of infographics listed the top players in each region, followed by some global statistics. The original infographics can be found here.

Top players

The performance of individual players was broken down by region, and by a number of criteria. Some of these statistics are collated for all regions below. As a rule China and Asia tallied higher numbers of total wins, runs and 12-win runs, compared to the Europe and Americas regions. The individual class records were mostly claimed by the Americas region, while the Europe region dominated in areas related to average run performances.

• Highest average number of wins per run: Caesar (EU) with 8.090
  • The second and third highest also went to the EU with Pollitos at 7.991 and Woett at 7.692
• Highest number of 12-win runs in total: ggcnm (China) with 152 12-win runs
• Highest number of wins in total: ggcnm (China) with 8,378 wins
• Longest streak of 7+ win runs: Woett (EU) with 17

Notes

• The players with the highest average number of wins per run were selected from those with at least 100 runs. Designer Dean Ayala states that there were players with higher averages, but all below 100 runs, and mostly below 25 runs.
• Although not mentioned above, the Americas player with the second highest average number of wins per run was BattlePants, which is actually a 'smurf' account belonging to well-known streamer Hafu.

Overall stats

The following stats were presented collated for all regions, for January-September 2016 period. Additional stats can be found in the original infographics.

• Number of hours spent in Arena games: 157,872,547 hours
  • Number of turns: 6.31 billion turns
• Most drafted cards:
  • Common: Piloted Shredder, Jeweled Scarab, Tomb Spider
  • Rare: Sludge Belcher, Azure Drake, Sunwalker
  • Epic: Piloted Sky Golem, Kodorider, Grand Crusader
  • Legendary: Dr. Boom, Arch-Thief Rafaam, Ragnaros the Firelord
• Least drafted:
  • Common: Warsong Commander, Moonfire, Totemic Might
  • Rare: Savagery, Cursed Blade, Darkshire Librarian
  • Epic: Siltfin Spiritwalker, Embrace the Shadow, Tentacles for Arms
  • Legendary: Acidmaw, Nat, the Darkfisher, Herald Volazj
• Most of one card in a single deck: 9 copies. A Light in the Darkness is shown, but there may be other examples.

Notes

• The Arena run with 9 copies of A Light in the Darkness went 3-3.

Design

The design of the Arena provides for a very different way of playing Hearthstone than that found in constructed play. In comparison, Arena rewards players based more on their ability to construct decks from a less than ideal selection of cards, and to improvise in unlikely match circumstances. It also features a greater emphasis on basic gameplay skills, rather than complex strategies and specific gimmicks. Arena is far less dependent upon knowledge of the current meta, and sees far fewer highly organised decks, but frequently features unlikely, improvised and sometimes extraordinary plays which can be extremely hard to predict.

Arena also provides a second chance for cards rarely seen in constructed play. Many cards widely considered poor choices for constructed decks are presented to players as Arena picks, and end up finding their way into players' decks. Because of this, the diversity of cards seen in Arena is far greater than that of constructed, again contributing to a greater focus on improvisation in response to unexpected circumstances. This is one answer to the often asked questions regarding the existence of certain seemingly poor cards; while they may rarely be chosen in constructed, their presence in Arena broadens the variety of the game mode, and allows it to offer almost an additional set of cards to that seen in constructed play. Not only does their presence provide a greater range of options, but due to the random nature of Arena picks, these otherwise panned cards have the opportunity in Arena to become valuable and even game-winning choices, due in part to the other unlikely cards presented to players when constructing their decks.

Because of the far greater difficulty in constructing a deck with a specific design, knowledge of the current meta, and the ability to play around a central gimmick or specific strategy are far less valuable in the Arena. Improvisational skills are highly important, both in responding to an unpredictable opponent and in playing a less than ideally constructed deck. Players cannot rely on a common sense expectation of what the opponent's deck should hold, nor on a consistent or balanced deck of their own. While "net-decking" the latest top-ranked decklists can provide great advantage in constructed, Arena is far more rewarding of a knowledge of the constituent parts of a deck, and the many ways in which they can be combined when ideal opportunities fail to present themselves.

For these reasons, a different type of player can expect to shine in Arena than in constructed play. While it is possible for players to excel at both, many will find themselves consistently seeing more success in one type of play than in the other. Players with a greater knowledge of the current meta and a focus upon refining specific decks and strategies will likely fare better in constructed, while those less well-versed in the latest trends may have a better chance in the Arena. The lack of opportunity for ideal deck construction allows players with less advanced deck building knowledge a greater chance of success, with familiarity with the latest decklist less valuable than a shrewd instinct for the basic building blocks of the game.

Arena can also provide a break from the relatively construction-focused domain of constructed play. While success in constructed often requires constant tweaks to a deck, and may punish players who do not keep an eye on the latest developments in the meta, a deck made in Arena cannot be changed, and once built must be played as is for better or worse. This can allow players to simply enjoy doing their best under less than ideal circumstances, without excessive focus on where they could have improved the deck, especially considering the great variety between the cards offered in each Arena run.

Arena also gives players a chance to experience many interesting and hard to obtain cards which they may not have the opportunity to play with in the rest of the game. While higher rarity cards are relatively uncommon picks, Arena is the only mode besides the limited realm of adventures' Class Challenges (and certain Tavern Brawls) in which players can play with cards that they do not actually own. This can provide great insight into which cards to craft, or simply highlight the fun of playing with cards the player has never chosen to experiment with. The variety of classes found in Arena can also give players an opportunity to experience playing with classes they do not often choose, as well as sampling those classes' higher rarity cards and higher basic cards, which the player may not yet have earned.

Notes

• It is possible for a player to be matched twice against the same player over the course of a single Arena run. For example, if player A defeats player B, but then loses their next game, while player B is defeated by player A but then wins their next game, the two players will be a viable match-up for their third games. However, given the large player pools this is very rarely seen.
• Rarity is on average far more significant in Arena than in any other game mode. While in constructed play rarity mostly affects new players who have not yet collected higher rarity cards, with higher level players usually having already collected all desired cards, in Arena rarity randomly determines card selection options, affecting players at all levels. Rarity also affects game balance far more in Arena than in constructed. In higher level constructed play, the only impact of rarity is that legendary cards are limited to one copy per deck. In Arena, the decision of what rarity to give a card determines which options it will be matched against, and how frequently it will appear, increasing the likelihood of players having several copies of the card in a deck. Both of these factors mean rarity will directly determine how often a card shows up in Arena, making the rarity of certain cards a common subject of discussion for Arena players.

Development

An early iteration of the drafting process

Initial

The Arena - originally titled 'The Forge' - was first conceived as a way to incorporate 'draft mode' style play into the game. Drafting with a physical CCG involved players passing round packs of cards, drawing individual cards until they had each built a deck - something many of the developers enjoyed, but which would be difficult to implement within Hearthstone. To solve this problem, the developers implemented asynchronous drafting, allowing each player to separately - yet randomly - build, or 'forge' a unique deck.

Early versions of the Forge had players keeping all the cards they drew for their deck. Admission cost several card packs, and would win packs in exchange for achieving wins. One snapshot of the development process shows the player earning a pack for each win above 4, with 10, 15 and 20 wins granting 5, 15, and 30 additional packs.

The Forge originally had an admission fee of 3 card packs

The developers eventually decided to remove both the card pack admission cost, and the reward of keeping the chosen cards. One reason for this was to remove the conflict between whether to choose the card that was better for the current Arena run, or the card which the player ultimately wanted to add to their collection. This change allowed players to focus purely on building the best possible Arena deck. Another reason for the change was to remove restrictions on which cards were presented. When the player kept the chosen cards, it was necessary for the range of cards presented for selection to match those which would have been obtained if the player had simply opened the card packs spent to enter the Arena. This ensured the result was fair, but also tied the developers' hands for Arena balance. By no longer allowing players to keep the cards chosen, the developers were free to adjust the balance of rarity to make more exciting Arena runs, as well as including cards from other sets, where before only Classic (then called Expert) cards were featured.

The Forge, in early 2013, showing an almost finished interface

The change also removed the necessity for players to choose whether to open their card packs or spend them to gain access to the Arena, where previously spending card packs might see players unable to keep cards they would have kept if they had simply opened the packs. While players still had to choose where to spend their gold (and real money), the change removed the "horrible tension" of this choice, allowing players to simply enjoy opening card packs without these concerns.

These changes were accompanied by the change of name from the Forge to the Arena. The change was in response to feedback from internal testing, where players often mistook the Forge for the game's crafting mode, believing it was where you went to "forge" new cards. While the term accurately described "forging" a new deck, it was also confusing in that it didn't evoke combat or battle against other players, which was ultimately the main focus of the mode. The new name "The Arena" was chosen to clearly indicate the gladiatorial nature of the mode.

The Forge's reward scheme

The rewards for the Arena were also iterated upon. Prior to the shift from the Forge to the Arena, rewards came in the form of card packs, directly compensating players for the admission fee. A screenshot from early 2013 shows players earning one card pack for every win, starting with their fifth victory. Extra card packs were awarded upon reaching certain milestones, with reaching 20 wins awarding a bonus of 30 additional card packs. The milestones stated also reflect the Forge's lack of limit to the length of runs in the game mode's early versions. The arrival of the Arena saw the key system introduced, with each win earning a new key, and a maximum of 9 wins. This was later increased to a maximum of 12 in December 2013.

Following the Arena's emergence in the late alpha, and during most of the beta, the fixed system of card pack rewards was exchanged for a number of smaller random rewards. In early Arena builds the number of rewards did not vary dependent on the number of wins, only the contents of the rewards themselves. A player with only 1 win would still win 5 rewards, but these might consist only of 5 gold, 5 gold, 5 gold, 10 dust and a card pack. This was changed in December 2013's Patch 1.0.0.4217, with both the number and quality of rewards now scaling with wins. The exact rewards have since been tweaked a number of times, but this general scheme has remained in place.

Ongoing

All new cards are designed to take into account both Play mode and Arena games. However, the developers acknowledge that some cards "get way better" in Arena than in Play mode, and vice versa.

History

Card exclusions

The first cards to be excluded from the Arena were those of the Promo set, namely Gelbin Mekkatorque and Elite Tauren Chieftain, likely due to their initially being available only through special promotions. With only two cards excluded, and both of those rarely seeing play in any game mode, Arena essentially used the full card pool for the first 2-3 years of the game's life.

It was not until the release of Whispers of the Old Gods in April 2016 that the first major exclusions were made, with C'Thun and all related cards being specifically excluded from the drafting process. These were excluded due to their specific synergy, with the likelihood of drafting enough such cards to prove effective being extremely low.

On August 8, 2016, after receiving negative feedback over the upcoming Purify and the weakness of the priest class in the Arena, Ben Brode announced that Purify would not appear in Arena drafts. This marked the first time a card had been excluded due to Arena balance concerns over its poorness, as opposed to the general lack of synergy of the C'Thun cards.

While the exclusion helped to mitigate frustration over Purify, the community's desire for improvements to the game mode's balance in general prompted the developers to move up the schedule on some planned changes to the format. In a reddit post on September 6, 2016, Ben Brode explained that while the developers had plans in motion to improve the situation in the "medium-long term", the community discussion had made them "rethink our timelines and options". As a result, on September 8, 2016, Blizzard announced that an additional 45 cards would be removed from the Arena in an effort to rebalance the classes. This was by far the biggest set of exclusions to date, as well as the biggest change yet to the game mode as a whole. The developers explained that the goal of the exclusions was to reduce the power of mage and rogue - long the most successful classes in Arena - and to increase the power of all other classes, except for paladin, which was already at around the desired power level. When selecting cards, the developers tried not to exclude 'story cards', or to remove too much class identity.

Move to Standard and changes to card probabilities

In September 2016 the developers mentioned that they were planning changes to improve the balance of Arena play in the "medium-long term". This saw a number of specific card exclusions from Arena, which are documented above. A few months after the card exclusions, the developers commented that they were still "working on a more elegant system" to balance the game mode.

In February 2017 the most substantial changes to the format yet were announced. Most significantly (and controversially), the Arena was changed from Wild to Standard format. In addition, a number of specific rules modifications were announced to the base probability of cards showing up in drafts: Common, Basic, and neutral Classic cards would show up less in drafts, while spells would show up more often in drafts. Abyssal Enforcer and Flamestrike were also specifically given a 50% reduced chance of appearing in drafts. A less critical change was the long-awaited addition of golden cards to the format, something that had been requested since the game's beta.

With the release of the Journey to Un'Goro expansion, Quest cards followed in the footsteps of C'Thun cards in being banned from Arena due to their lack of sufficient synergy in non-constructed decks.

The hero cards from the Knights of the Frozen Throne expansion were initially available in the Arena upon launch, but on November 14, 2017, they were removed from the draft pool since "while the Death Knight Hero Cards are exciting and powerful to play, their permanent Hero Power upgrades are hard to combat in a format where answers are limited".

Trivia

• While the game client itself does not feature seasons for Arena play, some regions may offer special promotions rewarding performance in the Arena. On June 1, 2016, the official Chinese Hearthstone site announced that the players with the highest number of 12 win-runs each month would be eligible for special prizes, including tickets to BlizzCon 2016. This was a Chinese initiative, but the game's developers intend to learn from the results of the experiment.
• The symbols used for keys 4-10 are the same as the original Ranked play medals, in use for most of the game's closed beta. The first 3 keys are slight variations on the first 2 Ranked medals, although some of the keys have been given different names.
• With Whispers of the Old Gods the legendary minion C'Thun and the 16 cards that offer specific synergy with it were the first new cards since the release of Elite Tauren Chieftain during the game's closed beta to be specifically excluded from the Arena. The 17 cards also represented the largest proportion of excluded cards until September 15, 2016 when an additional 45 cards were excluded.
• Following the reveal of Purify from One Night in Karazhan, along with the video response regarding the card's design, it was also announced that the card will not be available in Arena, due to its limited synergy applications and possibly from community backlash.
• On March 22, 2016, streamer TwoBiers became the first known Hearthstone player to successfully complete the 100 in 10 Arena Challenge.

Quotes

When selected at the start of a run, each hero will speak a unique soundbite, similar to an emote. These quotes are also heard in the Heroes tab of the Collection.

Alleria	You have my bow.
Anduin	I won't let you down.
Arthas	Justice has come!
Garrosh	None are stronger than I!
Gul'dan	Embrace the shadow.
Jaina	My magic will prevail!
Khadgar	Wisdom is greater than strength.
Lady Liadrin	I will serve! For Shattrath.
Magni	I'm ready! Let's do it.
Maiev	Now is the time!
Malfurion	You were right to awaken me!
Medivh	My plans are falling into place.
Nemsy	Ho ho! This is going to be fun.
Rexxar	Only beasts are above deceit.
Thrall	Storm, earth, and fire, heed my call!
Tyrande	The Goddess calls.
Uther	I will serve!
Valeera	They'll never see it coming.

Gallery

At the end of the run...	…the facade burns away...	…allowing the key to unlock...
…the Arena vault...	…releasing the player's rewards	Purchasing admission to the Arena

Patch changes

• Patch 9.2.0.21517 (2017-10-17):
  • Vicious Fledgling can no longer be drafted.
  • Removed synergy picks.
  • Small appearance rate adjustments.
• Patch 9.0.0.20457 (2017-08-08):
  • Arena Rewards: Reduced variance of rewards in Arena. In particular, reward bags will no longer contain single, non-Golden Common cards.
  • Arena Draft Change – The first two sets of cards in a draft are now more likely to include synergy-based cards.
• Patch 7.1.0.17720 (2017-02-28):
  • Creating decks for the Arena will now feature Standard cards only. Arena runs that were started prior to the patch will still include Wild cards.
  • Rares, Epics, and Legendaries will be offered more frequently during Arena deckbuilding.
  • Spells will now show up with a higher frequency.
  • Neutral Basic / Classic cards will appear less often.
  • If you own a Golden version of a card, the first copy you draft will be Golden. If you own multiple Golden copies of a card, all copies you draft will be Golden.
• Patch 6.1.1.14406 (2016-09-15): 45 further class cards have been excluded from the Arena selection process:
  • Druid: Savagery - Poison Seeds - Soul of the Forest - Mark of Nature - Tree of Life - Astral Communion
  • Hunter: Starving Buzzard - Call Pet - Timber Wolf - Cobra Shot - Lock and Load - Dart Trap - Snipe
  • Mage: Forgotten Torch - Snowchugger - Faceless Summoner
  • Paladin: No exclusions
  • Priest: Mind Blast - Shadowbomber - Lightwell - Power Word: Glory - Confuse - Convert - Inner Fire
  • Rogue: Goblin Auto-Barber - Undercity Valiant
  • Shaman: Vitality Totem - Dust Devil - Totemic Might - Ancestral Healing -Dunemaul Shaman - Windspeaker
  • Warlock: Anima Golem - Sacrificial Pact - Curse of Rafaam - Sense Demons - Void Crusher - Reliquary Seeker - Succubus
  • Warrior: Warsong Commander - Bolster - Charge - Bouncing Blade - Axe Flinger - Rampage - Ogre Warmaul
• Patch 5.0.0.12574 (2016-04-24): The guaranteed pack from Arena runs will now always be from the most recently released expansion. Additionally, you are slightly more likely to receive a second card pack from a different Standard set.
• Patch 4.2.0.12051 (2016-03-14): The sound effect when picking a card in Arena is now quieter, and varies in pitch.
• Patch 3.0.0.9786 (2015-08-18):
  • Players will now have a chance to receive any of the current Hearthstone card packs (which include the Classic Hearthstone set, Goblins vs Gnomes, and The Grand Tournament) whenever a card pack is awarded, with a greater chance to receive The Grand Tournament card packs.
  • Achieving 12 wins in the Arena is now accompanied by a message from the Innkeeper: "Ooh! You have claimed the top arena prize, the Lightforge Key!".
• Patch 2.7.0.9166 (2015-06-15): Heroes are now golden in the Arena if the player has 500 wins in Ranked play with that hero.
• Patch 2.0.0.7234 (2014-12-04):
  • Some heroes have new unique emotes when selected at the start of an arena run.
  • All card pack Arena rewards are now Goblins vs Gnomes card packs.
• Patch 1.0.0.4944 (Open beta, 2014-03-11): Arena rewards at 10, 11, and 12 wins no longer reward common non-golden cards.
• Patch 1.0.0.4217 (Closed beta, 2013-12-10):
  • The number of matches you can win in Arena has increased to 12 (up from 9).
  • Arena rewards have been restructured.
• Unknown late alpha or early beta patch: Rewards of 5 Arcane Dust have been replaced with non-golden common cards.
• Patch 1.0.0.3388 (Alpha, 2013-06-22):
  • 'The Forge' has been renamed 'Arena'. [Undocumented change.]
  • Players no longer keep the cards they select in the Arena, and admission now costs gold instead of card packs. [Undocumented change.]

External links

• Inside the Arena (2016-10-18)
• Hearthside Chat: Upcoming Arena Changes with Dean Ayala (2016-09-08)
• The Key to the Hearthstone Arena - Overview blog (2013-08-01)