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.
Jonathan doesn't treat Dio as an irredeemable villian. Literally everyone else (including Dio) sees him as an irredeemable villian which is hilarious as Dio basically does everything he could possibly do to make him being victim of this trope be comically silly only to succeed not because Jonathan gave up on him but because he fucking died. Leaving him to cope with absorbing his friend's body and starting a cult in Egypt. Actually thats kinda the reverse of this trope isn't it? Yeah we need more Dios.