Azoth, Spirit Rider

At the beginning of your upkeep you pay life less
than or equal to the number of creature cards in
your graveyard.
Whenever you lose life add {r} to your mana pool
for each 4 life you lost.
{r}{r}, {t}, Sacrifice a creature: Target player loses
life equal to the life you lost this turn. You gain
life equal to the number of creature cards in your
graveyard.