The Witcher – Uchiha Madara!

Waking up in the body of a 6-year-old boy a few years before Cintra is destroyed, Madara receives a system that gives him the ability to gain the powers of Uchiha Madara.

[The peak of Uchiha Madara's system is before he becomes the ten-tails jinchuuriki.]

The system's percentage does not stop Madara's power, but rather the system's release. After all, I don't want to see a character who goes around killing everyone from the beginning of the story.