You can lie to John about lore pretty easily bc he remembers very little from his eldritch deity days. He'll distrust this guy on vibes alone.

Definitely! Other powerful characters can sense that John is an eldritch entity possessing a human body (but he's a podcast character, so we don't know exactly what they see). Feel free to use any of this:

John is anchored primarily in this body's eyes. He's specifically a piece of "the King in Yellow," who is twice the size of a human and cloaked in trailing, tendril-like tatters of beautiful amber light. John normally has the ability to project that form beyond this human body, though he hasn't regained that power yet in the jamjar. His only permanent, visible monster transformation in-game is a yellow radiance in his eyes when he's startled or emotional.