I'm not sure but base on what I can recall, priest-san is locked up on the holy nation (?) central church basement. It is because he tried to hide Pharma from the other priests. Why, you ask? It's because they want to lock up the Medicine God (aka Pharma) to be exploited and so he cannot leave Earth. Base on the lore, I think descended gods typically return after a short period of time (like 2 ~ 4 yrs) and they don't want that thus they capture all that have full marks of gods. Anyway, priest-san is scheduled to be removed his god arts but Pharma will save him and that's where Pharma will learn that he can also remove other's god arts
It's about a reincarnator (? not sure) FMC that helps the ML become strong while staying anonymous. She sends the ML into missions and such so he will get strong. However, she abandons him in the end to build her own team. So ML goes look for her and strongarm her to include him in her team. Additional info I can remember is that there are some Chess related terms used in the story and the ML have a fire related power. Thanks a lot in advance to those who will help