Niku, Draconian Awakener

Whenever another nontoken, non-Dragon creature you control is sacrificed, return it to
the battlefield face down under its owner's control.
It's a 4/4 red Dragon creature with flying.

Sacrifice a nontoken, non-Dragon creature:
add {b}{r}{g}. Spend this mana only to cast Dragon spells.

"Secede to the flame within, and be reborn."