[Dr Kain]

So I need to ask, but who the hell does Absorbing Man belong to? I mean, I've had this dude sitting in my case for the last several years as he was a Spider-Man BAF, but he's not a Spider-Man villain. I've never even seen him fight Spider-Man. He made his first appearanced in a Thor comic, but then he fought Hulk in that terrible early 2000s movie. After that, he fought DD's father in a boxing match in the MCU, so he's not a Hulk villain there, and he appeared in Agents of Shield as a good guy. Who is he actually a villain to?