Remorseless Dreadkite

Flying, ward —Sacrifice a nonland permanent.

When this creature enters or attacks, you may pay
{1}{b} any number of times. When you pay this cost one or more times, put that many -1/-1 counters on each creature your opponents control.

Whenever a creature an opponent controls dies, if its toughness was less than 1, create a 2/2 black Zombie creature token with menace.