Amaterasu

"This," Setsuna stated. "is the fire that consumes all. The fire that needs no fuel, as it is driven by a sentience beyond our limited, mortal comprehension. The fire that forever hungers, and solely exists to reduce the world to nothingness. The fire that will burn for seven days and seven nights."
"This is Void Fire, boya. A blessing, and a curse, all Void Kitsune are born with. The Uchiha call it Amaterasu. It's a stupid name: there's nothing remotely divine about it."