Honestly them being siblings is like not really a big deal to me lol.. for sion and Mary(forgot her name already) being and thinking of each other as siblings is normal since they grew up together in a way that ends with them being siblings, they see each other as siblings (at least what I see from mary) so they're siblings. But sion and mc are in love, mc likes sion and sion likes mc in a love interest way so they'll naturally unconsciously distance themselves from the sibling kind of dynamics/thinking, even if they do grow up together. Kinda like those childhood friends to lovers stories, if anything they'll probably unconsciously go to the dynamic they had in the original time line.
I really like this series but I really wish she wasn’t adopted by the duke T-T I know she’s doing it so she can protect Aiden (aka her dad even tho she has no clue) but idk I’m just not a fan of it lmao,, also now what’s going to happen with Sion? Because he can’t be adopted by the duke now since they’d become siblings and that’s just.. Eugh. I almost wish they went with like a sponsorship or deal route where Tainia is like “let’s make a deal!” With the duke in exchange for her dad becoming a knight or something.. I DONT KNOW?? PLEASE DONF BASH ME IN THE REPLIES I STILL REALLY LIKE THIS SERIES