I Cultivated a Nemesis

The demon king possesses a regression ability, but is continuously killed by his nemesis. Finally, he chooses to regress, but then he becomes the older brother of his nemesis. He decides to use his abilities and raise his nemesis to become useless, but this began to go in an unexpected direction. **Original Webtoon:** [BiliBili Manhua](https://manga.bilibili.com/detail/mc35892)