Target

A target is a specific character that a player action is "aimed at". Targeted effects are those that require a target to play, while others are untargeted. A spell, Hero Power, or Battlecry may be targeted, while one character's attack on another is always targeted. Choose One and Combo effects work exactly like Battlecries for targeting purposes.

Targets are often selected by players as part of taking actions. Other times, cards choose targets randomly, or always affect a predetermined target. Players can only choose one target per action, although that may cause additional effects which apply to characters beyond the target. Those that choose randomly may also affect multiple targets. Some Triggered effects may switch an effect's target to a different character than originally chosen.

Generally, both friendly and enemy characters may be targets. Some abilities place restrictions on which targets are valid. Players cannot choose "no target" if a valid one exists, even if that means targeting a friendly minion with a harmful effect or vice versa. Sometimes this can be surprisingly beneficial, if a normally harmful effect would actually be helpful due to the specific situation or card.

One of the priorities of the Hearthstone game designers was to make the game quick and easy to interact with. For this reason, the only time targets need to be selected by players is when they initiate actions on their turn. Additionally, character-to-character targeting always indicates an attack action, although triggered effects may cause subsequent side effects from the attack.

See Random effect for more details on random target selection.

Targeting restrictions
Many player-selected and most randomly selected targets have restrictions beyond "a character", while abilities that always hit the same target of course must specify what that target is. The most common distinctions are between enemy or friendly characters, and between heroes and minions. Most hero-specific effects also specify whether it is the player's hero or the opponent's, although Alexstrasza may target either one. If a card only specifies "enemies", it refers to the enemy hero as well. Many other restrictions are also possible, based on minion type, statistics, and text/abilities. As of Whispers of the Old Gods, Steamwheedle Sniper is the only card that changes the targeting of another effect, specifically turning an auto-targeted ability into a player-directed one.

These targeting restrictions can sometimes make random effects not at all random due to the existence of only one valid target (or set of targets).

Elusive minions cannot being targeted by either player's spells and Hero Powers. However, they can still be hit with randomly targeted or untargeted effects, and can be selected by players making attacks or playing Battlecries. Stealth and Immune prevent all player targeting from the opponent only, although they too can be hit by random or untargeted effects. Immune, of course, has the additional benefit of preventing damage even if it is hit. This makes it especially inconvenient to employ random targeting against an opponent using an Immune character, which may absorb hits that could otherwise have damaged more vulnerable targets.

"Permanent" minions cannot be targeted, including by random target or AoE effects. Despite this, they still take up places on the battlefield, and will effectively 'soak' positional effects such as Flametongue Totem or Cone of Cold without effect.

Spells, Hero Powers, and weapon Battlecries

 * See also: Spell, Hero Power, Weapon

Targets are selected for spells, Hero Powers, and weapon Battlecries in the same way. The text below uses the collective term "action" to refer to all of those plays, and "card" to specify a spell or weapon played from the hand.

Targeting of player-chosen actions is done by selecting a playable card or Power and then selecting the target character. Actions for which there is insufficient mana are unplayable and cannot initiate this process; the same is true for Hero Powers that are exhausted for that turn. A bold red arrow leads from the action source to the intended target, moving as different selections are made. The opponent can see the targeting arrow as well during this process. The opponent's view includes the hand position of the card being played (or shows that it is the Hero Power), but the identity of the card is not revealed until the play is actually "locked in". If the target is valid, the action will complete. If the target is invalid, an error message will be presented, and if the player targets an empty area, the action is cancelled - in either of these cases no card is revealed. Players cannot take an action and choose "no target" if it normally requires one, which in some cases forces players to select non-ideal targets to gain from side effects of the play.

For automatically selected targets, whether random or predetermined, the player simply drags the card onto the board or clicks the Hero Power, and target selection is handled by the game.

When there are no valid targets at all, different consequences occur depending on the card and type of targeting. Specific notes can be found on card pages.
 * A spell or Power requiring a player-chosen target, for instance Fireblast or Swipe, can never be used without one.
 * When the target(s) are random characters, a spell or Hero Power can generally not be played without at least the stated number of valid random targets, for instance 1 enemy minion for Deadly Shot or 2 for Cleave. However, if a spell has a mix of random and untargeted effects, it may be castable even without targets - for instance Sabotage works to destroy a weapon even with no enemy minions in play.
 * Weapons with random Battlecries can be played regardless of available targets, even if that means their Battlecries have no effect.

Minion Battlecries

 * See also: Summon, Battlecry, Choose One, or Combo

Most minions are played from the hand to an empty slot on the player's board with no targeting. However, those with Battlecries or related abilities may cause targeted effects. Players can never select the Battlecry card as its own target, and there are no Battlecry cards that include themselves in randomly targeted effects.

All minion plays begin the same way: first selecting a playable minion (the player must have enough mana) from the hand and then selecting the desired board position. Most minions would be put into play at this point, but an additional targeting step takes place for a minion with a player-targeted Battlecry. Similarly to spells, a bold red arrow leads from the minion being played to the intended target, moving as different selections are made. The opponent can see the targeting arrow as well during this process, except from their perspective the card will still be in the hand, since it has not actually been played at this point, making it indistinguishable from a spell. The arrow reveals the hand position of the minion being played, but its identity is not shown until a target has been finalized. If the target is valid, the minion summoning will be completed. If the target is invalid, an error message will be presented. If the player targets an empty area, the minion play is cancelled or "undone": the minion is not revealed, its selected board position is "forgotten", and it is visually returned to the hand, which it never truly left.

For automatically targeted Battlecries, whether random or predetermined, the player simply drags the minion into the desired board position as with any other, and target selection is handled by the game. If a minion has a player-targeted Battlecry but there are no valid targets, it is played as if it had no Battlecry at all - once the board position is selected, the minion is summoned and the Battlecry has no effect.

Note that if any valid target is available for a Battlecry, the minion cannot be played without selecting one. As with spells, players wishing to play minions with situationally inconvenient Battlecries may be forced to select friendly targets for detrimental effects, or enemy minions for beneficial ones, in order to get the minions onto the board. Unlike spells however, minions are never prevented from being played due to a lack of Battlecry targets.

Attacks
When attacking, the target is often called the "defender". All attacks are ordered by selecting an attack-capable character and using the targeting arrow that appears to select the desired defender. As with the other targeting actions, the arrow is visible to both players even before the attack order is completed. A player may commence the attack by selecting a valid target, will get an error message if selecting an invalid target, and can cancel the attack by selecting empty space or by right-clicking. Only enemy characters may be targeted in an attack, but certain triggered effects may change the defender to a new character, including a friendly one, before combat begins. Some effects may even cancel the attack entirely, in which case the player may initiate a new attack without being bound by previous targeting choices.

Attacking characters can generally target any enemy that is not Immune or in Stealth. However, enemy Taunt minions restrict the valid targets for an attack to only those with Taunt.

It is extremely rare for there to be no targets to attack, since either the opposing hero or a Taunt minion should be attackable nearly all the time. Thus, only an Immune opponent with no attackable minions, such as a warlock with a Stealthed Mal'Ganis, could result in such a situation. In this case, no attacks can be targeted, so no attacks can be ordered at all.