They are basically super saiyans with wolverine genes. And btw what i say is true because a lot of people dont know or forget that Invincible started as a parody of shonen mangas and Marvel/DC comics overall.

There are like hundreds of CLEAR references to other comics. But when it got too popular, they have to create a unique story since you cant keep going as a parody forever if you wanna have smt for real.

I actually think the opposite. Mark didnt beat the shit out of them, if Nolan wasnt OP, they both would die.

And the reason why Mark was able to keep up with the fight later was simple, Nolan says it outloud. Mark isnt a viltrumite, he doesnt fight to kill. He fights expecting the other side give up. So when Nolan gave him some Goku speech, he just fought for his life instead of trying to protect his enemies too.

And also there is one other reason too but that would be a spoiler.

What happened to “make a search before you post something” manner in reddit overall?

You wonder about it? Nice, go search for it, you will see a lot of the same topics, there are a lot of answers too.