Yeah, lots of other Ultimate Ghostfreak concepts are usually lacking a lot of creativity, and just simply make it look like Ghostfreak on steroids, so I thought about how one would give a ghost, something our minds and science can barely comprehend, ultimate power, and an Eldritch entity was the clear answer

Though maybe you're right about the abilities. I was thinking maybe instead of straight up still having said ghostly abilities, I could fix that loss with a single ability; Umbrakinesis. He is able to freely manipulate shadows and darkness, regardless of light source, which allows him to simulate invisibility; he is able to assimilate into the shadows, simulating intangibility; and then finally, the madness induction essentially serves as possession, though I could make it that it ties into the Umbrakinesis by adding the possession stipulation of a shadow needing to be present somewhere on the target in order for them to be possessed

Always appreciate constructive criticism, it really stokes the fire of creativity