Syr Harren the Abandoned

At the beginning of your endstep, if you have
gained 4 or more life this turn, you may return
Syr Harren the Abandoned from your graveyard
to the battlefield.
Whenever another non token creature you
control dies, exile it from your graveyard and
create a 1/1 white skeleton creature. If the
skeleton would leave the battlefield, return the
exiled card to your graveyard.