Arranged

Kiera is the bastard child of Count Charon and a Witch from beyond an Outrealm gate, fully adopted into the family begrudgingly by his wife. She spent most of her childhood in the imperial palace as Dimitri's playmate as her family did not want her around but we're not above using her to improve the family's standing. As they grew, Kiera became like the sister Dimitri needed and showed an incredible aptitude for an odd kind of magic unseen in all of Foldlan. Dimitri clung to Kiera after the tragedy of Duscur and they both believed that the slaughter that took place was a plot to behead the kingdom of its most powerful and influential people carried out by someone who wanted to pin the blame on the people of Duscur.

Growing jealous of the influence Kiera held over the next king of the Holy Kingdom of Faerghus, Count Charon's wife decided to arrange a marriage for Kiera to one of the worst nobles in the Adrestian empire. Count Bathory. The young woman's birth mother buys her time by gaining her late admittance to a school of magic in her home realm. Kiera ran away to attend her fifth year at Hogwarts at the age of fifteen, turning sixteen shortly before school began when she would have been forced to marry the Adrestian count known for his wives dying suspiciously untimely deaths.

Dimitri attempts to find a way to prevent Kiera from leaving him permanently. The one way he can protect her from marrying that madman would be to have her marry someone else but she outright refused to marry him because she didn't want the power or expectations that came with being queen. So who could he find to marry his best friend to protect her from her crazy family?

Fire Emblem 3 Houses/3 hopes x Hogwarts Legacy crossover