Fire Nation Sentinels

Whenever another creature you control dies, put a +1/+1 counter on this creature.

Flying

Whenever you cycle or discard another card, put a -1/-1 counter on each creature your opponents control.

Cycling (, Discard this card: Draw a card.)

Vigilance (Attacking doesn't cause this creature to tap.)

When Sephiroth enters, creatures your opponents control get -2/-2 until end of turn.

Whenever a creature an opponent controls dies, put a +1/+1 counter on Sephiroth.

Menace

Whenever a nontoken Knight you control dies, each opponent loses 1 life and you draw a card.

Flying

When this creature enters, destroy target creature an opponent controls.

Whenever a creature an opponent controls dies, exile it and put a +1/+1 counter on each Vampire you control.

Flying

Whenever a creature an opponent controls dies, you create a Blood token. (It's an artifact with ", , Discard a card, Sacrifice this token: Draw a card.")

Whenever you sacrifice an artifact, put a +1/+1 counter on this creature and you gain 1 life.