Kechibi

The Kechibi (けち火, Ill-Omen Fire) is a unique Sword in the possession of Haigara Sarutobi. It is a blade derived from the Chakra Blades principle, and dramatically enhances Haigara's capabilities with the Fire Release nature. Despite its worn-out appearance, it actually is capable of frightening cutting ability and overall power, making it a remarkably underestimated blade.

Trivia

 * are humans that have turned into balls of fire. Their appearances are shown to be human faces etched onto the fireballs.