Shadow Of The Mist

Shadow Of The Mist,

Someday, within the walls of Konohagakure's prison a boy awakens a system. With it he gains access to a kekkai genkai that was never awakened before. He uses this power to gain more from the system, getting some strange memories and other rewards after accomplishing tasks from it.

No typical: MC gets system and is instant op'' story. His kekkai genkai is, in my opinion, not as strong as the sharingan, but can be if used in the right way.