voici la règle:
603.6d Normally, objects that exist immediately after an event are checked to see if the event
matched any trigger conditions. Continuous effects that exist at that time are used to determine
what the trigger conditions are and what the objects involved in the event look like. However,
some triggered abilities must be treated specially because the object with the ability may no
longer be on the battlefield, may have moved to a hand or library, or may no longer be
controlled by the appropriate player. The game has to “look back in time” to determine if these
abilities trigger. Leaves-the-battlefield abilities, abilities that trigger when a permanent phases
out, abilities that trigger when an object that all players can see is put into a hand or library,
abilities that trigger specifically when an object becomes unattached, abilities that trigger when
a player loses control of an object, and abilities that trigger when a player planeswalks away
from a plane will trigger based on their existence, and the appearance of objects, prior to the
event rather than afterward.
Quand une capacité se déclenche spécifiquement quand des permanents quittent le champ de bataille, on regarde l'état du jeu juste avant cet événement pour voir ce qui se déclenche. A ce moment, la guivre est encore sur le champ de bataille donc sa capacité se déclenche.
