Alright so I'm sure most of us think he is Vanitas which is what I thought at first but what if he's someone else? Y'all remember Ansem with the brown coat in Kingdom Hearts 1 before he had his SOD form? Well it's said that he had no form and considering that the new Org. XIII has different forms of Xehanort in it maybe it's him? After all, he did have no form and it would make sense.

 

If that theory doesn't make sense then he's probably Vanitas. The only reason why I doubt he's Vanitas is because those eyes he has aren't Unversed eyes and the novels don't contain 100% accurate information.

 

Anti Black Coat isn't a new character so he's either another form of Xehanort or Vanitas.

Wasn't it confirmed to be the darkness within Sora taken form as a Nightmare?

Wasn't it confirmed to be the darkness within Sora taken form as a Nightmare?

To be honest, I'm not sure. But if it was I'm pretty sure I would have read it in the comments section on youtube by now.

Maybe it's a Disney Character that joined Org XIII I could see if it was Oswald (If you don't know who Oswald is, he's basically Mickey's Older Brother because he was Walt Disney's first cartoon Character)

i think its simply nightmare, resembling Roxas and Soras heartless at same time.

It could have been Vanitas as in the novelization of Birth by Sleep it is said that, when Vanitas came to life, he had red eyes and no face. But It has been confirmed (I think) that it's just the darkness inside Sora's heart.

Wasn't it confirmed to be the darkness within Sora taken form as a Nightmare?

 

Sora's darkness personified as a Nightmare.

I say it's Vanitas.

I hope its Vanitas mostly because I want him to return in KH3

I don't think Anti-Coat has any ties to Xehanort at all. He came straight from Sora, and is his Nightmare. I feel like Anti-Coat is just a reflection of all the negative things the people in Sora's heart have gone through. Roxa's grief, Xion's forgotten existence, Ventus's broken heart, etc.