Gen, the Forgotten Druid

Sacrifice a creature or land: Until end of turn, you
may play target card from your graveyard. If that
card would be put into your graveyard this turn,
exile it instead. Put an age counter on Gen, then,
if Gen has 3 or more age counters, sacrifice him.
When Gen dies, return him to the battlefield transformed.

Many disapproved of his macabre methods, until he
was shunt to the fringes of society.