Also, I think our boi rokudou will end up with raino. I think author points to this happening quite a bit and by now this is conformation that a solid flag is raised for them to be together.
On the other hand, Ranna's disposition is too... special for her to become a lover. I think the relationship between her and rokudou is very complicated compared to others since her very existence is evil and she is literally nothing else besides that. I'm really curious how her situation will be resolved because I have a strong feeling rokudou's power will end eventually, although it's possible since this is a comedy series too this might not be the case, or it may disappear for a bit and then resurface. It's infuriating that she's such a major obstacle to raino and rokudou but that's how the story has been since forever. Rokudou recognizes this and wants to resolve that first, since he knows in essence he has control over someone by controlling their emotions, something he despises about himself.