Demonology and Coherence Theory of Truth

After Monday's class, a thought occurred to me about coherence theory of truth. Allow me to play it out in a sort of thought experiment.

Let's say I want to make a completely outlandish claim, say, for example, that I can perform magics such as summoning demons from an outer plane of existence. I can build up an entire system of theory around this that would be perfectly coherent, and has no connection to the real world (or perhaps I should say the "apparently real world"). Would this then be truth?

Perhaps I should be more clear. I could certainly create this system and then use it as the basis of, say, a fantasy story (something that is quite common in that genre). However, as this system is only workable on paper, and flies in direct contradiction to the laws and principles governing our plane of existence, it would be truth in the story, but not truth in our plane of existence.

Or would it?

This may be further complicated by possibility. Nothing can exist without the possibility of it existing. The possibility exists that I could summon a demon to do my bidding and enslave the earth, but the method by which I may do this may or may not exist in our plane of being. So is it truth, then, or fabrication?

As a final note, I will likely continue to post on my aesthetics blog as I find interesting news articles related to art (as I have today). If you have an interest, I encourage you to check it out.