Hey again, that's actually a simple and elegant solution. Yeah, usually in pathfinder the demon lords/demi-deities equivalent essentially stop at CR 30 with their mythic powers.
Thank you everybody for your insights. It does seem like it would take some extra efforts to mix them and trying to balance it out (wouldn't be impossible tho) but so far leaning toward just using the Immortal Handbook and tweak a few things to be more compatible with the whole thing, mythic...
Since I imagine many of you have played with Pathfinder 1st edition probably, was just curious of the interaction of the system with Mythic Adventures (Yes I know Mythic can be pretty ridiculous), anything that I should look for or advice in general when using PF and Immortal Handbook? or would...