I mean, the drawer made some cool and seems like unnecessary character design for a bunch of guys who weren't really described/deepened in the ln. I bet they didn't change anything big in the plot but maybe we got some backstories or something like that. And yeah, there were the translator, the manager and Goto. But he wasn't really a slow headed guy he was just over the top egoist/who looked down on everyone. He simply couldnt belive that our mc is that much stronger than him (why he thought that he is an assasin, mc just too strong in fistfight to be a sorcerer) cause at "his world", where he is the top of the top, he extremly rarely saw anyone better than him.