Blaze Release

is an advanced chakra nature kekkei genkai of the Uchiha clan, that lets them produce black flames. Sasuke Uchiha uses this technique when manipulating the unquenchable black flames of Amaterasu, fashioning them into various weapons and defences. C states that Sasuke manipulates the flames with his right Mangekyō Sharingan whereas he casts Amaterasu with his left. It is unknown what element(s) this nature entails aside from Fire Release which makes up Amaterasu.

Trivia

 * Upon seeing Sasuke Uchiha perform Blaze Release: Susanoo Kagutsuchi in Scorch Release: Halo Gale Jet Black Arrow Style Zero, Tobirama Senju noted that he had never seen such usage of Kagutsuchi. This implies that there has been at least one other Blaze Release user before Sasuke Uchiha that lived during Tobirama's lifetime.