Riziel, the Cursed Warden

Vigilance, Deathtouch, Haste
Whenever a Knight you control dies, target
opponent sacrifices a creature.
Whenever a Demon enters the battlefield under
your control, look at the top five cards of your
library. If you do, you may reveal a Knight card
among them and put it into your hand.
{r}{r}{r}: Creatures gain double strike until the
end of turn.