Permissive keyword
Reaction
Reaction is a Permissive keyword.
Defined by rule 813. and its 17 sub-rules. Every rule number below opens that rule in the rules browser.
Rules
Reaction
Reaction is a Permissive keyword.
It can be present on Cards, Rune Abilities, Legend Abilities and Permanent Abilities.
Reaction grants the corresponding card or effect all abilities and permissions of Action.
Reaction, additionally, is functionally short for the following:
On Cards: "This can be played during Closed States on any player's turn."
On Activated Abilities: "This can be activated during Closed States on any player's turn."
Reaction is formatted as “[Reaction]” on cards, or “[Reaction], [>]” on abilities.
The corresponding card or effect with this keyword is not restricted to Closed States or Showdowns. This permission is inclusive of all other timings and options available to the ability as written, Action's permissions, or by default.
Reaction does not alter the function of any instruction of the Card, Rune, or Effect it is on. It is only Permission.
Playing Units with Reaction still has the inherent restrictions of playing Units without Reaction. It can only be played to the controlling player's base or a battlefield they control.
Some passive abilities may grant a card or ability Reaction under certain conditions. The card or ability does not have the Reaction keyword unless and until those circumstances are true.
Those conditions might only be fulfilled while the card or ability is on the chain. In such a case, it can still be played or activated at the appropriate timing as long as doing so could fulfill the conditions.
If the chain item does not fulfill the conditions by the time step 5: check legality has been reached, the actions taken while playing it are undone and it is returned to the zone it was played from if it is a card.
Reaction is a referencable characteristic.
Whether or not a Game Object has Reaction is a characteristic of that Game Object and may be checked or referenced by other Game Effects.
Whether or not a Spell has Reaction is a characteristic of that Spell and may be checked or referenced by other Game Effects.
Whether or not an Ability has Reaction is a characteristic of that Ability and may be checked or referenced by other Game Effects.