Well, without having read it, it could potentially center around a transformation where a non - human entity becomes human just for one night. It could explore how this new human form affects their interactions with other characters, their understanding of the human world, and perhaps there are some adventures or romances that occur during this one - night - only human experience.
Toge Inumaki is important too. His special cursed speech ability makes him stand out. Also, the principal of the school, Masamichi Yaga, is likely to be important as he is in a position of authority and has an influence on Gojo and the other students. There could be other characters like the members of different clans that also play roles in the complex web of the story.
I'm not sure as I haven't read it specifically. But generally, a love novel might have themes like the journey of falling in love, the challenges faced by the couple, and the growth of the relationship.