https://www.novelupdates.com/series/the-hero-returns/ Regression. MC is the last person on earth to survive. Everyone else was killed fighting “Fafnir” the Predator who noshes on worlds. MC is the most powerful Awakened on earth, and he dies at last fighting an impossible enemy. He wakes up, and realizes he’s gone back in time. He gets very strong, very quickly. Unlike other regression novels, he uses his brain. He’s constantly asking questions. It is on WebNovel, but of course alternative places to read exist. It’s good, you will like. He’s not the kill everyone, and enslave the survivors, like some Korean regression novels. He is trying to be kind. However, he got taken advantage of, because of his kind nature in the past life, so he’s way more stern and ruthless. He does compassionate things in secret, though.