Kiri-Hel, Mindmage of Tolso

At the beginning of your upkeep, if there are no
cards in your library, you may pay {4}{u}. If you
do, you win the game.
{t}, {1}{u}{u}: Target player mills four cards. Draw
a card.
{t}, {5}{b}{b}: Return target creature from a
graveyard to battlefield under your
control.