My theory is he was adopted as a heir to the family and actually has no blood relationship to either of the sisters and is expected to marry one of the sisters to still keep the title with the main family. That's why he keeps pushing our MC because he prefers her to Blondie.
Yeah that's plausible
Isn't the other sister is a step sister? if he was actually bought in to inherit the family then it would make the most sense for him to marry the MC cause she's the only one blood related to the father.
it’s probably because she was originally f-rank that that didn’t happen though
Ok so help me out. Is he her brother? I don't think he is step brother since the maid didn't mention him during that convo, and also that would make blood brother with the blond girl and that would get weird. And what's all obsession with marrying ur sibling in this manga. I'm confused(。=｀ω´=)?