739. Reaction

739.1. Reaction is a Permissive keyword.

739.1.a. It can be present on Spells, Units, Rune Abilities, Legend Abilities and Permanent Abilities.
739.1.b. Reaction grants the corresponding card or effect all abilities and permissions of Action.
739.1.c. Reaction , additionally, is functionally short for the following:
739.1.c.1. On Spells: "This can be played during Closed States on any player's turn."
739.1.c.2. On Units: "This can be played during Closed States on any player's turn."
739.1.c.3. On Rune, Legend, or Permanent Abilities: "This can be activated during Closed States on any player's turn."

739.2. 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.

739.3. Reaction does not alter the function of any instruction of the Card, Rune, or Effect it is on. It is only Permission.

739.3.a. 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.

739.4. Reaction is a referencable characteristic.

739.4.a. 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.
739.4.b. Whether or not a Spell has Reaction is a characteristic of that Spell and may be checked or referenced by other Game Effects.
739.4.c. Whether or not an Ability has Reaction is a characteristic of that Ability and may be checked or referenced by other Game Effects.