Riddian Demon of Wrath

Sacrifice a Human creature you control, add {b}{b} to your mana pool.
Whenever you sacrifice a creature, Riddian
Demon of Wrath gets your choice of a flying,
trample or +1/+1 counter.
If Riddian Demon of Wrath has a power of 6 or
higher you may pay {b}{r}{r} and pay 2 life to take control of a Human creature an opponent
controls.