Ne'Hai Iyel, Avatar of the End

Sacrifice another creature: Put X +1/+1 counters on
Ne'Hai Iyel where X is the power of the sacrificed creature.
Whenever Ne'Hai Iyel destroys a creature, put
X +1/+1 counters on Ne'Hai Iyel where X is the
power of the destroyed creature.
At the beginning of your upkeep, if a creature was
not sacrificed or destroyed last turn by Ne'Hai Iyel,
you lose X life where X is Ne'Hai Iyel's power.