Sister of Cold Nights

Indestructible. When Sister of Cold Nights
enters the battlefield, sacrifice a creature or
sacrifice Sister of Cold Nights.
{t}: Add a curse counter to target creature.
Any creature with a curse counter loses all other
counters at the next end step.
"Unhuman hands shall tear your body into pieces,
upon a field of battle, yet you shall know no respite -
thus, my curse upon you, Sister of Cold Nights"
-High King Kallor