The rival.
Especially the douchebag Machiavellian type rivals that the main character ends up friends or teaming up with after the main character 'proves their worth' to them by being stronger. No character growth outside of now they work with the protagonist.
I really want this trope to be subverted one day, like the douchey rival shows up and everyone is just like "Wow what a dickhead" and just relentlessly bullies him until he goes away.
Yeah, but Griffith gets his comeuppance for his pride by getting his life ruined due to his own actions while Guts continues to grow before coming back to rescue him. I haven't finished the Golden Age arc yet, but I'm sure they must learn to be best friends and equals as Guts helps Griffith come to terms with his new life as a shell of his former self, right? I can't wait to see what wacky hijinks they get up to next!
I can't comment without major spoilers. When you finish the golden age arc you'll see what I mean.
I've read all of Berserk, I'm just seeing how many "oofs" I could collect from people reading that.