I Became Friends with the Second Cutest Girl in My Class (WN) - Chapter 269

Hiding in the Cold Palace and eventually becoming a Boss of Sorts. Li Mu was transported to a fantastical world and became a measly eunuch of the State of Xia. Despite having initially thought that his life would be a miserable one, he had unexpectedly acquired a check-in system.

There was a woman. Born as an illegitimate child and raised under the strict control of the queen, her world was as small as a well.

There was a man. He was forced to marry a woman who was his brother’s political marriage partner. His world, which was infinitely wide, became smaller.

The woman’s original sin, and the man’s resentment. “I should have just died instead…”

Violence, Rogue, two names that had long since faded away from the limelight. In a new game, The Strange World, they appear once again. The two former legends, once more rise to glory.

- Description from Novelupdates

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.