Raven Branwen, Spring Maiden

Lifelink, Haste
At the beginning of each end step, put a +1/+1 counter on Raven Branwen, Spring Maiden.
{1}: Raven Branwen, Spring Maiden becomes a
1/2 black Bird creature with flying and haste
until end of turn. Activate only as a sorcery.
"The weak die, the strong live. Those are the rules."