Kelryn, Lord of Underkeep

Flying, Lifelink, Ward {3}
When a creature token enters the battlefield
under your control, put a +1/+1 counter on that
creature token.
{1}{w/u}{t}: Create a 1/1 white Spirit creature token.
If there are no other creatures under your control
on the battlefield, create 2 of these tokens instead.
{t}: Sacrifice {x} creatures. Destroy target creature
with toughness {x} or less.