Fenrir, the Shackled Plague

As an additional cost to cast this card, sacrifice
one "Tyr" card you control or discard one "Tyr"
card from your hand.
When this card enters the battlefield, it is exiled
with two shackle counters on it.
Whenever a God creature you or your opponent controls dies, remove one shackle counter from Fenrir, the Shackled Plague.
When Fenrir, the Shackled Plague has no shackle counters on it, it enters the battlefield with
vigilance and first strike.