Demonic Conquering

Put a +1/+1 counter on target creature. If it's a
Demon put an additional +1/+1 counter on the
creature. Then target creature you control fights
target creature your opponent controls. (Each
deals damage equal to its power to the other.)
"The king of demons, he can't be held back.
I'll hold him off, run men!"
—Kahvel, The First Demon Hunter