Believing you and your life are either literally or metaphorically the center of a metaphysical narrative in which you are the protagonist and that your life obstacles or people you disagree with or dislike are forces of evil. Most often seen in people who have consumed large amounts of entertainment such as books, movies, or video games which have a concrete "good or bad" for most of their lives.
"My sister in law keeps referencing Harry Potter online when politics are brought up. I think she may have a protagonist complex."
"Quit being so self righteous. You sound like you have a protagonist complex."
The Hentai Protagonist Haircut (or hph for short) is that generic haircut dudes get looking like a damnbowl on their head. Literally the most boring possible haircut a dude could get.
Person 1: Hey did you see Dane's recent haircut?
Person 2: No, what does it look like?
Person 1: He's sporting a damn Hentai Protagonist Haircut
When an Anime Protagonist is born, 1 or both of their parents are going to die very soon from "Anime Protagonist Disease".
Anime Protagonist: *is born with blue hair Doctor: i'm sorry to say this, but you now have Anime Protagonist Disease
Mother: Do i have to die or him?
Father: why not BOTH?!