Kari Nela, Fang of Vish Kal

First Strike, Deathtouch
Whenever you cast an enchantment spell,
you get an experience counter.
When you gain 5 experience counters, Kari Nela, Fang of Vish Kal deals X damage to
any target. You gain X life, where X is the number of creatures in target opponents graveyard.