That’s just straight up groom culture. And the author didn’t even try to justify it, not that it would be even if they did try.
Oookay after seeing snippets of the side story which is super long and all about Mary and Eden it seems like this author lost the plot and is obsessed with unhealthy age gap relationships. The main series ending feels totally creepy now. Would not be surprised if it becomes Usagi Drop type shit.
The age gap could have been compelling if written well, even though it's still concerning no matter what. I think the author definitely tried to do that in the start, but let it fall apart as the storyline went on, like you said. There's nothing "slice of life" or "fluffy" about marrying off a newborn or a child you raised as practically your own family. That's practically inbreeding.
Yea, I don't really have a problem with with it in the right genre but this series is not. I felt like the dragon siblings were being set up for an arc that would resolve their fiance situation before the plot got derailed. Who knows if that's really what the author intended or their actual views on grooming children but when the story ends with a grown ass man hovering around a child that he put a tracker on it really can't afford that ambiguity.
Probably unpopular opinion but the dragons' social dynamics give me the ick. If your culture can't sustain itself without age gaps so huge one spouse basically grooms the other from childhood or even birth maybe it deserves to die out? It's not ever really addressed either.