This is more because I want to know if others thought the same as me, rather than asking to confirm whether it's like that.

 

Since the Anti Black Coat Nightmare we fight as Riku in Dream Drop Distance is the nightmare of Sora given a form, I just thought there is a reason for why it's exactly this form. It's just a black coat, although with red glowing eyes and some violet markings on it, so I guess Sora may be a bit scared of the Organization after all. Not scared as in cowering in fear just at the thought of them, but Sora is a boy of 15 years and they are the bad guys, of course he'd be a bit "scared". Just because you're bravely going 'round slaying them, doesn't mean you can't be scared of them. So I think his nightmare took the form of a black coat, which all the Organization members and also those of the new Organization wear, but of course it's a bit altered as most nightmares aren't just straight to the point either. To sora, black coat means bad. That the sole good guy (Axel) he met wore one doesn't necessarily change that. 

 

So yeah, dunno if I'm a bit slow since millions of other KH fans may have already had that Ahh!-moment or don't care at all. I just want to tell everyone, when I think if something lol.

Never thought of it that way.  I always thought it was just some kind of Phantom, but your theory is pretty awesome.  Now that I think of it, don't you think that thing could be one of the Thirteen Darknessess?  Nah, I don't think so. X3

But wait , the fact that Sora managed to beat the Org.XIII members means that he is not scared of them .He's probably just "scared" or "be afraid of" the black coats . Not the "beings" wearing them .

Never thought of it that way.  I always thought it was just some kind of Phantom, but your theory is pretty awesome.  Now that I think of it, don't you think that thing could be one of the Thirteen Darknessess?  Nah, I don't think so. X3

It's not exactly a theory, more like a thought haha. No, I don't think so, I think other than wearing the (almost) same coat, it has nothing to do with Xehanort or the Organization. 

 

 

But wait , the fact that Sora managed to beat the Org.XIII members means that he is not scared of them .He's probably just "scared" or "be afraid of" the black coats . Not the "beings" wearing them .

 

To sora, black coat means bad.

That's actually what I wanted to say with this. But what made it bad to Sora in the first place were still the Organization members and by extension also Xehanort. Also that feeling might have become stronger directly during KH3D, because he was literally harassed by black coats (Young Xehanort, Xemnas..) and he was surrounded by all of them in TWTNW too, which was the closest event to when Riku meets the Nightmare and fights it.