You're in the pov of Xeno/Kokabiel. So you see what he sees. You're him right now. Anyways.. You just look around and you see something that no one knows or sees. Then Xeno remember (You also remember) Xeno's/Your hallucination talks to you

Arcanum: "Hello God Kokabiel or Xeno! Arcanum is here! How are you?"

Xeno says (You also say cuz you're him right now): "Arcanus.. I'm not alright as usual.." Then Xeno/You realize that he/you see hallucinations again.

"OH DAMN..." Xeno and you put his/ur hands on his/your head

"I was seeing hallucinations again..."

So you realize that that ghost is just a hallucination. No wonder why no one (including you) knows.. Then Xeno sees that ghost again, you also see since you're in Xeno's pov. This time you decide to ask what that ghost it. But remember. You're just talking to your hallucination and you're Xeno. You can talk to ur imaginary friend Arcanum before it goes. It comes back though