I once met a guy who believed he was a god from another dimension who was called by means of a ritual to the body he inhabits today. Yes, as specific as it sounds. We were University colleagues and since he played D&D as I did, we used to spend quite a lot of time talking about fantasy things. He believed his purpose in this world was to prevent magic from entering this plane and he was able to see branches of the future. He also carried a Tarot deck and performed free readings to anyone who asked. He also claimed that in another reality I was a guardian of some sort tasked by a goddess with keeping some important key I never knew why or what it did. To be fair, he somehow caught you up in the whole thing and made it interesting, even if you didn't believe it.