Board Thread:Naruto Discussions/@comment-25051328-20140818021248/@comment-25294339-20140819225556

Jashin Uchiha wrote: Sasuke stated he had three Mangekyō Sharingan powers to awaken Susanoo. "The third power... Susanoo." Kagutsutchi is merely manipulation of something a water release jutsu is Suiton: Kagutsutchi (basically its not even a jutsu), so that can't be the other power. He dosen't have Kamui or Kotoamatsukami so he must have Tsukuyomi. With his right eye, Sasuke manipulates the flames. Amaterasu is cast with the left, and because Amaterasu is cast with one eye and is considered as one the the Mangekyō powers bestowed upon the wielder, Katgutsuchi is the third power.

To be frank, its pretty cool too, controlling the black flames and all.