Rule 191.4

For Abilities, they are the Ability’s Controller.

• 191.4.a By default, the Controller of an Ability’s Source is the Controller of that Ability.
• 191.4.b Changes to Control of an Ability’s Source do not change Control of that Ability.
• 191.4.c That player chooses targets.
• 191.4.d That player chooses modes.
• 191.4.e That player pays costs.

Official Core Rules