Krovikan Vampire

If a creature Krovikan Vampire dealt damage to dies, then leaves the graveyard by some means, the game loses track of it. Krovikan Vampire’s ability won’t be able to return it to the battlefield, even if it’s put back into the graveyard before the end step.

At the beginning of each end step, the game checks all creatures that died that turn to see if Krovikan Vampire had dealt damage to them during the turn. It doesn’t matter whether the damage was combat damage, and it doesn’t matter whether the damage was what caused the creatures to die.

If Krovikan Vampire isn’t on the battlefield at the beginning of the end step, its ability won’t trigger. No cards will be returned to the battlefield, even if Krovikan Vampire dealt damage to some creatures that died that turn.