Against The Sky Supreme

In the God Realm, Tan Yun stood as a Supreme, basically one of the most powerful beings in existence. Then his own comrades stabbed him in the back during a demonic invasion, and he died. Not the best day. But death isn't permanent when reincarnation is on the table, and Tan Yun wakes up in a new life on the Tianfa Continent, stuck in a weak body with a family that treats him like garbage. The catch is, fragments of his old memories and abilities start surfacing, and suddenly this kid everyone writes off has the knowledge of a god-tier cultivator rattling around in his head. The world-building here is genuinely layered: inner universe versus outer universe, demons ruling one side, a mortal realm feeding into the Eternal Realm and the Realm of Gods, nine immortal emperors overseeing different star fields. It's a lot, but the show rolls it out gradually as Tan Yun climbs back toward his former power. If you liked the reincarnation-with-past-knowledge setup in Tales of Demons and Gods, or the massive cultivation hierarchy in Soul Land, this hits a similar nerve. There's also a revenge thread running underneath everything that gives it some of the darker energy you'd find in Mo Dao Zu Shi, though the tone stays more action-forward. At 580 episodes as an ONA, the pacing keeps things moving in short bursts. It's a long ride, but the power progression stays satisfying if you're into watching someone claw their way back from nothing.