@dulcce I think if you look for the castle in a variety of romance isekais, i dont entirely remember from the top of my head. but i did see the castle like 3 other times in other series
dude did he have her when he was 18 or 20 or something, he looks way too young to be a father unless he was also super young when he slept with someone and had a kid xD If he was 36 or 38 then yeah I'd probably be more accepting of how young he looks ^_^;;;;