Thank you I'm in desperate need for spoilers ahh
(ʃƪ＾3＾）thank u
Spoilers
Iirc, Zeref actually still is her brother, since they have the same mother. The Emperor hates Zeref because Zeref isn't his son, but is actually a product of the Empress' infidelity. The family tree is actually quite confusing lol, I can't quite remember all their names but essentially,
Emperor + Empress = Cayena
Raphael's dad + Empress = Zeref
Raphael's dad + Raphael's mum = Raphael
Emperor + his lover = Ethel
Like why tf the king's mad about his wife cheating ..like he has a lover too so their even even (◡ ω ◡)
the princess cayena's brother the prince, is actually not her blood related brother but just an adopted son of the king. I don't know the whole backstory, but the king admitted it when the duke raphaelo came to visit him in his bed while he is sick. the king wanted the duke to marry her daughter, princess cayena, and be the rightful king instead of the non-blood related son like the prince. this means that the prince in currently being obsessed with the princess and not because they are attached because they are siblings.
soon, the prince may realize his true identity and become the real villain between the duke and the princess cayena's relationship. but i hope that they could get marry before that happens.
oh, and one more thing. there will be a secret relationship building between princess cayena and the prince's assistant (which i don't know who the fuck is) so we might become a bit annoyed for the decision princess cayena will make.
this is based on the novel i have read, and I haven't read the updated chapters yet. so i hope this somehow solve your other curiosities.