Who could be the main antagonist in a 'Captain America weight gain fanfic'?

The Night King could be a great antagonist. His army of the dead and his own powerful magic would pose a huge threat to Captain America. Cap's used to fighting human foes, but the Night King is something entirely different.

The Penguin could be a great antagonist. He might mock Catwoman for her weight gain, using it to try and undermine her confidence and take over her territory in Gotham.

Maybe it's an old enemy who has somehow survived and is now more powerful. They could be seeking revenge on Captain America for past defeats. For example, Red Skull could have found a new way to return and cause trouble.

It could be a rogue Amazon who disagrees with the idea of an outsider like Captain America being on Themyscira. She might see him as a threat to their way of life and try to drive him out, or even worse, harm him.

Well, in the 'Captain America weight gain fanfic', it could be that he is mind - controlled to overeat. Imagine an enemy using some sort of mind - control device to make Steve Rogers consume large amounts of food. Or perhaps he's on a mission in a place where food is scarce, but when he finally gets access to it, he overindulges because of the long - term deprivation. This could lead to a significant weight gain. Also, it could be a story where he has to adapt to a new civilian life after a long time as Captain America and the change in routine and diet causes him to put on pounds.

Obviously, Bowser would be one of the main characters as it's about his weight gain.

An alien race with a grudge against the Republic could also be the main antagonist. They might target Rex specifically because of his strategic importance and his role in leading many successful missions against them in the past. His death at their hands would be a major blow to the Republic's morale.

Thanos could still be a great antagonist even in a fanfic. He could come back with a new plan to obtain the Infinity Stones again. His powerful and menacing presence would create a high - stakes situation for Captain Marvel and the Avengers to face.

He could also meet Odin. Odin might view Captain America as an interesting mortal from Midgard and might have some words of wisdom or a task for him to complete during his stay in Asgard.

Well, Cersei herself is obviously a main character. Since it's a fanfic about her weight gain, the story would revolve around her experiences, emotions, and how she deals with this change.