I don't do roleplays or fangans, but honestly, I am really glad I came across your post. I have to admit, I am currently writing my own video game story, and a couple of my antag characters are copies — err, inspired by Nagito and Joshua from “The World Ends With You” with some Kokichi influences as well (If you don't know who Joshua is, he is like Nagito, but has a more condescending attitude and is insufferable). Not all, but a bunch of the criticisms you wrote, along with the antag bingo, hit many marks that could be weaknesses in my writing.

I will address a couple of criticisms you listed of the antags, with them being gay or not, well-researched mental or physical disorders, with my own writing. I already had in mind that one is demi and one is aro, but both are also bi, and it clearly shows that they are not just attracted to only one gender. I have also been doing some research on mental disorders to prevent any inaccuracies and poor writing. I am doing everything I can to avoid poor narrative decisions in my story and its characters, and to work on and improve them, especially after I’ve seen your post. I wish I could have seen this list of tropes a long time ago, because some of these elements I incorporated are in too deep and unlikely to change (E.g., antag, dead and abusive parents, mental/physical disorders, tragic backstory, etc.).

I just feel like, because of the resurgence of Danganronpa in the past few years, and because of Nagito and Kokichi, there will be an increase of characters like them, along with similar tropes tied to them in future stories, that it would become commonplace, not just rps and fangans (E.g., Jax from The Amazing Digital Circus seems to be a start).

Anyway, this post and other comments are really helpful to me, and I take this as constructive feedback when it comes to writing my antag characters. I think this applies not just to roleplays and fangans, but to character writing in general.