Rainenmaru

Rainenmaru was one of Contract::Suien's summons who appeared in Naruto: Mission: Protect The Waterfall Village! (novel).

Personality
Rainenmaru was very loyal to Suien. He was also violent towards his opponents.

Appearance
Rainenmaru was a giant black koi.

Abilities
Rainenmaru had incredible speed and was powerful enough to take down Ryūrimaru and Naruto Uzumaki with a single blow.