The Simple Life of Killing Demons - Chapter 17Book 12:

After annihilating Han, Zhao and Wei empires in succession, the dynasty of Qin is ushering in an unprecedented flourishing age with powerful cultivators emerging endlessly. People take pride in being part of the Qin dynasty. However, Ding Ning, a young lad of humble origin in Changling, Qin, is determined to subvert this dynasty and kill the emperor who breaks in the Eighth Realm.

He died on the wedding of the girl he had a crush on, after a long and successful career. After convincing Yama to send him back to the world, he decides to fix the areas in which his life went wrong. Realizing the lack of love and romance in his past life, he sets out to conquer the hearts of various women.

Reborn as Red Army Misha!

- Description from novelbuddy

A man is reborn into the world of Avatar: The Last Air Bender as a waterbender from Katara's tribe. Best of all, he was the same age as her, and he had a system with him to help.He knows the future and a system that lets him continuously get stronger by completing quests or long-term missions, as well as giving him the ability to copy abilities from others for himself. He will become invincible in the world of Avatar, even more so than the Avatar himself.