Viridescent Crown also has the FL wanting to get together with her step-brother
http://www.mangago.zone/read-manga/recording_hall/?FpBj
Sweet Home Alabama~~
i think the problem is more that he saw her as trash before and even executed her. Also... he knew her as a child while he was older. Sexualising her when he knew her as a child and saw her grow up is quite creepy, I mean she's still quite young.
Also actually him liking her being a creepy thing is more common sense than most manga out there lol that would be the normal reaction, manga with step brothers being interested in the sister they grew up with are also creepy, the author and readers just romanticise it.
ikr
and now theres the precious sister of the grand duke too
honesty cain liking aria isnt even a big deaal in manga like in beaware of the brothers the fl had a good relatioship with her brother who ended up as the ml its super gross but more and more manga keep doing it