There are several cards that let me gain control of a creature “for as long as” I control the first card or that card remains on the battlefield (e. g.
Cytoplast Manipulator,
Dragonlord Silumgar,
Merieke Ri Berit,
Olivia Voldaren,
Roil Elemental,
Rubinia Soulsinger,
Seasinger,
Sower of Temptation or
Willbreaker).
After I have gained control of an opponent's creature which has an ability “Whenever a(nother) creature dies” (e. g.
Deathgreeter,
Murder of Crows,
Rage Thrower or
Reaper of the Wilds), my opponent destroys my creature (e. g. with
Murder).
This will let my opponent regain control of his creature as well as trigger the ability of that creature.
The obvious question is: Who is the controller of that triggered ability, i. e. who gets to choose the targets, gain life, scry, draw/discard cards etc.?
It is clear that my opponent is already the controller of his creature again when the ability is put on the stack. But according to CR 112.8 the controller of a triggered ability “is the player who controlled the ability's source when it triggered”. And I wonder whether the control-changing effect has already ended at that time.
(My guess: Because it's a zone-change trigger, the game looks at the moment immediately before the event, when I was still the controller of my opponent's creature, and so I would be the controller of the triggered ability on the stack.)
Thank you.
Kind regards,
Mario Hassler