The main couple is actually pretty good (I'm not sure what's the age gap, but mc seems like a young adult to me, not a teenager) BUT the world building is just too out there, there's no explanation to most of the conflicts/major plot moving events, like the reasoning on such a bloody cruel war between humans X beasts, or anything about mc character's family really. The romance is good, but rest of the story could use some development, maybe if there was another vol to explore it?
Musebinake, Junjou