CR / RELEASE 2026-07-24
Rule 417.6.b
If a game effect does specify a source, then that source is what is considered the origin of the Damage for this Deal action.
Rule hierarchy
Direct children
417.6.b.1Units and Spells can be the source of Damage for Deal actions.417.6.b.2Abilities can be the source of Damage for Deal actions.417.6.b.3When a spell or ability specifies a Unit as the source of the Damage for the Deal action, it is not in addition to the spell or ability that instructed it. Example: Challenge is a spell that reads “Choose a friendly unit and an enemy unit. They deal damage equal to their Mights to each other.” The damage that Challenge causes to be dealt is dealt by the chosen units, not by Challenge.417.6.b.4The controller of the source of a Deal action is responsible for that Deal action unless the player performing the Deal action is otherwise specified. Example: If a player plays Challenge targeting a friendly unit and an enemy unit, the controller of the enemy unit is responsible for the damage dealt by their unit. Any effects that trigger “when you deal damage” that that player controls will trigger.