The Last Incubus with The Vice and Valor System - Chapter 100: Request...

The eternal night is coming, and the killing ground descends.Gods fall, and a hundred ghosts parade at night.You can stand in the forefront and announce the arrival of the era's tide to the world, or you can hide in the darkness and coldly observe the struggle of others to survive.Liberate your thoughts, embrace your destiny, this is the absolute real game, this is, Earth's Killing Field.

Our straight (?) bottom woke up ten years into the future and found himself on the bed of his childhood friend… At the start, the bottom was shocked to his very bones, but he soon quickly accepted this premise and found the whole situation to be rather amusing. Precisely then, the bottom once again went back to his timeline — back to when he and the top were just platonic childhood friends.

Chi Lang transmigrated to the Middle Ages as a third-rate magician in a third-rate magic academy. His magical aptitude is zero. But he has a good roommate.

His roommate is good-looking.

His roommate is good-natured.

His roommate helped him escape from danger several times.

His roommate never complains.

Chi Lang felt like he liked his roommate a little bit, and then his roommate helped him solve his ‘single’ problem.

It wasn’t until much later that he realized that his roommate was a remarkable figure.

——He was one of the demons sealed by the magician known as the “God of Magic”… And Chi Lang became the one who unlocked the seal of the Demon Lord.

- Description from Novelupdates

Protagonist travels between different anime worlds to right wrongs and uncover his reason for being along the way.