Crux of Crota

Crux of Crota enters the battlefield with X soul counters on it.
{t}: create an X/X black Taken Avatar creature
token, where X is the number of soul counters on
Crux of Crota.
{b}{ut}, sacrifice Crux of Crota: Target opponent
loses X life and you gain X life, where X is the
number of soul counters on Crux of Crota.