I'm looking for one of those goody goody "fight for justice" hero male protagonist. That basically fights anything that is evil or tries to harm his friends. He has a sweet gentle personality then something in him forces him to evil or becomes controlled/possessed, brainwash, or something tragic happens to become evil. For example, a superhero becomes possessed by some evil spirit forcing him to do bad things he would never do or a good guy who has something fighting inside him trying to take control. Or the mc whose being brainwashed by a evil organization and thinks he doing good.

so basically looking for an antihero? somewhere along the line he was changed? I doubt you will find someone who is tricked to do evil for the manga as the main character cuz usually those are side characters

Übel Blatt - main character is betrayed and becomes a rebel, was kind hearted and now is dark

Immortal Regis - main character starts good, changes in the sequel do to events

Akame ga Kiru! - main character wants to be warrior, changes after he sees the government, will be forced to harden emotions in coming chapters

Yugioh GX (The anime, anyway) not sure about the manga....

Try Tower of God or Toukyou Kushu:Re if you haven't

Blood Lad

It's nothing

Tokyo Ghoul and I second Tower of God 🙂
Try Arifureta - even though it's a korean webnovel it's really awesome - I think it's as good as an anime or a manga would be

Arifureta is a Japanese webnovel.

Source: I edited the damn thing, and marked Proofreader applicants' applications!