Firkle, Child of Darkness

Whenever Firkle, Child of Darkness deals damage
to an opponent, put one dark counter on that
card.
At the beginning of your upkeep, if there is 13 or
more dark counters on Firkle, Child of Darkness,
he gain the ability "At the beginning of your
upkeep, target player mills 13 cards".
"I like spiders, loss and rain. I'm only happy when
I'm in pain."