Well thats the Coded Unknown. He existed in the digitalized journal, but him and the digital Sora somehow made it's way into this "Real World" Disney's castle. We have no idea who he is right now, but I have a feeling the Organization cloak is a disguise. In the newer eposide of Coded the tranlation said it was a form of Riku. Which really doesn't make all that much sense. We'll just have to keep watching. Hopefully the truth comes out some enough.