Griffith, Hero of Midgard

Whenever Griffith enters the battlefield or another nontoken Human you control dies, you lose 1 life and create a 1/1 white Human creature token.
{2}: Target Human you control gains lifelink until end of turn.
At the beginning of your end step, if you have
exactly 13 life, you may pay {4}{b}{b} .
If you do, transform Griffith.