La Folia's sudden engagement declaration hits like a plot bomb because it forces Kojou to defend something he never agreed to, turning every fight into a negotiation he's already lost. Lucas is the kind of antagonist who makes perfect sense, he's not wrong to doubt some random high schooler, which means watching Kojou earn his respect becomes the actual story instead of just another power-flex. The OVA knows exactly what it is: two episodes of escalating chaos held together by a girl who decided her future before anyone else got a vote.

On their way to school, Kojou and Yukina come across La Folia fleeing from a huge man, and Yukina crosses swords with him. La Folia then reveals that the man is her father, Lucas, and that she has picked Kojou, the Fourth Progenitor, as the one she will marry. Lucas refuses to accept her choice, so her mother, Polifonia, invites Kojou and Yukina to a party to talk things over. When they get there, Asagi, Yaze, Nagisa and Sayaka turn out to be guests too, thanks to their ties to Kojou. Meanwhile, the Kingdom of Aldegyr is preparing for peace talks in Itogami City, and trouble strikes the royal family at the party. This two-episode original OVA mixes action, fantasy and ecchi comedy.