After doing some research on the character, it seems the OU of Anti Black Coat does not have any sort of a personality or character. We understand this AU serves as an attempt to give him one, and that's fine, but as it stands the application is a bit too sparse on details to be acceptable. So, here is some critique that we'd expect you to address in the revisions.
The history in particular feels sort of thrown together and confusing in terms of the canon. We really don't get a sense for what they were doing before and after the fight with Riku and between that and the subsequent fight with the whole island trio. Other than eating spirits, what was happening? Since nothing was really expounded upon, it looks like there's nothing much to the AU besides the existence of these characters. We understand that it's alternate, but the "universe" part is just not well crafted.
Another thing that's puzzling is that your version of ABC is a "Nightmare" form of Riku, but this is never really touched upon in the app beyond a passing mention. Does he have any 'Riku' traits? This is a point that could use some clarifying, since your sample seems to show something like that.
There's also the fact that this character is more similar to a fandom OC than an AU, and yet because he was an endgame boss, was born from Sora's nightmares, and looks like Riku, he's likely to have a strong IC response from the existing KH cast. We understand that all of these things are technically plausible in KH though, so this is a pretty unusual case in terms of acceptability. Because of that, we'd like to ask how you envision his reactions to the characters in-game.
Pending
The history in particular feels sort of thrown together and confusing in terms of the canon. We really don't get a sense for what they were doing before and after the fight with Riku and between that and the subsequent fight with the whole island trio. Other than eating spirits, what was happening? Since nothing was really expounded upon, it looks like there's nothing much to the AU besides the existence of these characters. We understand that it's alternate, but the "universe" part is just not well crafted.
Another thing that's puzzling is that your version of ABC is a "Nightmare" form of Riku, but this is never really touched upon in the app beyond a passing mention. Does he have any 'Riku' traits? This is a point that could use some clarifying, since your sample seems to show something like that.
There's also the fact that this character is more similar to a fandom OC than an AU, and yet because he was an endgame boss, was born from Sora's nightmares, and looks like Riku, he's likely to have a strong IC response from the existing KH cast. We understand that all of these things are technically plausible in KH though, so this is a pretty unusual case in terms of acceptability. Because of that, we'd like to ask how you envision his reactions to the characters in-game.