The Beautiful Fish-Tailed Boy I Picked up Is the Evil God of Destruction

I picked up a beautiful young man with amnesia at the beach. He had a fish tail and was as innocent as a piece of paper. I taught him how to read and eat, and treated him as the most precious treasure. Until that day when the whole ocean boiled and the sky was torn apart to save me from him. He hugged me, his eyes were crimson and crazy, but his voice was gentle and smiling: "Don't be afraid, although I do want to destroy this boring world... But now, I have found a reason to stay.