Game modifications, as said, don't have to follow the rules of the actual game. Plugins tend to do so because they ate literally additions to the game- addons, I prefer that term.
This section is intended for creativity and all that philosophical jazz. If someone wants to make an mvm mod, that's cool. This is covered in my next point.
As I said, there was quite literally no implication of that in this mod. Especially if you read the first post in this thread that has vikings aliens and anime freaks all over the poster. Many of the classes were either added by request or to parallel a forumer, some just because rubble wanted to add them. It's a big melting pot of a mod that adds a lot of junk.
And most of those anime freaks were from videogames, I'm just tossing that out there. Western videogames