What Demoness? She’s Obviously My Purehearted Junior Sister

[No System + anti-cliché + decisive killing + fast-paced + one female lead + lighthearted and funny + satisfying] Deng Jie finally achieves immortality, only to find that the Three Realms are on the brink of destruction. What he can’t believe is that the ruthless demoness destroying the Three Realms is the junior sister who once wouldn’t even kill a chicken! What happened to her over the past three thousand years? How did she go from gentle and kind to utterly depraved? Is it a loss of humanity or a collapse of morality? Deng Jie is sent back to the past to stop her. But simply telling her not to do evil doesn’t seem to solve the problem. If someone bullies you, are you supposed to swallow your anger? If someone deceives you, should you still show mercy? If you’re accused of something you never did, should you accept it without complaint? That’s not kindness. It’s cowardice! Instead of living such a cowardly life, he might as well let loose, fight his way through the bloodshed, and ask all the people under heaven: “What kind of demoness is she? She’s clearly my innocent little junior sister!”