Junior Brother, He Plays Me [Double Life] Every Day

On the day when blood stained the immortal mansion, I regretted the bowl of hot porridge I gave him that winter. I gave him warmth, and he became the Demon Emperor and took away everything from me. After being reborn, I decided to stay far away from him, preferably never to see him again. The new junior brother became famous in one battle and was accepted as the first disciple by the sect master. From then on, he embarked on the road of sword immortality. No matter what kind of monster he encountered, he never backed down. But why, once he encounters the Demon Emperor, he disappears without a trace... That day, I met the Demon Emperor again, and when the cold breath came over me, I called him in disbelief: "Junior brother?" His lip was bitten, his demonic pupils were burning, and his breath was disordered as he said, "Senior sister." * PS. The full text is in the third person. Intention: If you know your mistakes, you can correct them, and there is no greater good.