At age of 9 sasuke remember he's previous life, which made him more obsessed with revenge. He trained hard to avenge his clan, but he was killed by the Sage of Six Paths, the godlike creator of ninjutsu. When everything seemed to be lost, his system finally awakened. But the system had the wrong script: it asked him to pick up girls. Unfortunately for him, this was the only system he had.
First World: Harry Potter