I'm probably stating the obvious but I think he's the reincarnation of theo and only she can break the curse because they love each other, if not in this life then their past life 😀
Thanks for the chapters!
We saw Astina's past life say she'd curse Theodore but it was actually another person of the "witch" people her past life Martina was from who cursed that dickwad king, when he died the curse jumped to Theodore, when Theodore died it jumped to the Grand Duke family as dickwad and Theodore's Aunt was the grand duchess, which is why Thereode is cursed. Theodore knew the curse jumped to him which is why he had her kill him because he'd rather suicide by her than have her watch him slowly succumb to the curse. Which is honestly really fucked up