In Ultraman, I Become Brothers With Belial

Ultraman world + System + morally ambiguous + no female lead + nearly invincible + no saintly hero + chaotic timeline + decisive and ruthless + villain from the start. After transmigrating into the Ultraman world as a cocoon-form Zetton, he later rescues Belial, beats him into submission, and becomes his sworn brother. Right after he gets Belial out of prison, Ultraman King arrives and calls him an anomaly, intent on snuffing him out before he can grow. But for some reason, Ultraman King doesn't pursue him. Only later does he gradually realize that someone has been pulling the strings all along, and the truth slowly comes to light.

There are no eternal enemies!

This novel and its characters are entirely fictional. Any similarities are purely coincidental. Please do not imitate.