Heartbreaker Demon

Heartbreaker enters the battlefield with X +1+1 counters, where X is the number of white creatures on the field. If a white creature leaves the field, Heartbreaker gets -1-1.
If you cast another Heartbreaker, you gain X life, where X is the number of white spells.
After a battle, he stands over the field. Surveying all the hearts to feast on. You'll be lucky if he doesn't spot you faking death.