I've been thinking of how a country with the succubus religion as the state religion would look like, and have a theory that it could very well take on the form of a theocratic monarchy.
Please look at this link for a 'Christian' take on the matter which could originate from someone who thought deeper into this than I did; as we know, the succubus religion is supposed to take over christianity when it falls, as it has taken on a demonic disposition already in the sense that it is corrupted:
https://www.reddit.com/r/monarchism/comments/mi56ia/theocratic_monarchy_is_the_greatest_form_of/