So I know Fumeiyoshi is a god of envy among other things but I was wondering if he would ever form alliances with other deities. Particularly deities that are enemies of other deities that fall under "those who have good fortune they don't deserve" in his eyes. An Enemy of my Enemy is my Friend situation if you will.
This assumes he's not stuck in that tomb and is aware of the deities in question of course.
While they books don't specify any allies of Fumeiyoshi, in my campaigns I like to have divine connections- even from gods you didn't expect- that live in the same place.
So personally, I would say he might have a relation to the Ahriman (Who destroys cities and mortal legacies, which is something Fumeiyoshi would approve)- and maybe he ran across and have somewhat positive connection to the Daemon Harbingers of Mneoc, Osolmyr and Vorsha.
If you're looking for deities, I don't see a real reason for him to hate Lady Nanbyo- as she brings calamities to others.