The Extra's Return

[You have been killed by the Hero of Light.][You have died.]I had died at the hands of the main character in the novel I had read before.But I got another chance. I regressed and returned to the time when I first entered this novel world.Once again, I live in this novel world as an extra character.Since I have experience and knowledge, especially my World System which had upgraded, I'll do what I want to do.I will become stronger than the main character.