Blaze Release: Kagutsuchi

Blaze Release: Kagutsuchi is a technique which applies shape transformation to the black flames of Amaterasu, allowing the user to manipulate them at will. In Sasuke Uchiha's case, while Amaterasu is cast from his left eye, he uses his right eye to manipulate the flames.

Variants
The user can shape the flames in different varieties, for both offence and defence.
 * While using the ribcage state of Susanoo, the user can create a defensive encampment by manipulating the flames to cover it.
 * Converging the flames in front of the user, a barrier of spike-shaped flames can be created that not only shields him, but also pierces and burns any opponent that touches it.
 * The user can wield the flames in their hand without being incinerated, as well as manipulate them into a flexible sword which launches spike-shaped projectiles when swung.
 * The black flames can be used simultaneously with the Chidori to enhance the latter's destructive power.

Influence
Similar to other Mangekyō Sharingan abilities, Kagutsuchi's name is derived from Japanese myth and religion. Kagutsuchi is the God of Fire in Shinto and the one who brought death into the world by burning his mother, Izanami, to death as she gave birth to him. This made his father, Izanagi, kill him with the Sword of Totsuka.

Trivia

 * Sasuke's Susanoo is capable of wielding an orb of black flames, from which he can produce various weapons. Although the sword formed in this manner was initially identified as "Blaze Release: Kagutsuchi", it was later named as part of a derivative technique called "Blaze Release: Susanoo Kagutsuchi". In Naruto Shippūden: Ultimate Ninja Storm 3, it is named "Sword of Kagutsuchi".
 * In chapter 585, the furigana of this technique's name were written in hiragana, not in katakana, as they're usually written.
 * According to the fourth databook, Sasuke invented this technique when he fought A, but a reincarnated Tobirama Senju commented that he had seen it before during his lifetime.
 * In the anime, Sasuke is able to put out the black flames of Amaterasu using Kagutsuchi. This resembles the manga, where he put the black flames out as well, although this happened before his alleged invention of the technique.