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.
Saiyan's advocate: tbf, average saiyan children can tank bullets to the face, AND getting your ass whooped does actually make you stronger in this setting. Those two things considered, you have to understand that a warrior race's approach to raising children is going to be pretty freaky.
He's definitely done a few genocides though so he should probably be executed for that