Anime OVA: Kingdom of Valkyrja I, Strike The Blood Wiki

Kingdom of Valkyrja I (ヴァルキュリアの王国 前篇, Varukyuria no Ōkoku Zenpen) is the first episode of the two-part episode anime OVA. Kojou Akatsuki, with Yukina Himeragi, meet La Folia Rihavein's Lucas Rihavein and Polifonia Rihavein as Trine Halden spies on. Trine send Insect Swarm to attack the Rihaveins' party. Trine controls Kojou. Trine uses Kojou to kidnap Yukina and La Folia. Trine, interested with Kojou, spies on him from the rooftop of a nearby building from the restaurant where he is at together

I finished watching season 1 and im not sure in what order to watch the rest, its missing season 2 and skips to season 3 and then season 4 is called second.

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Anime OVA: Kingdom of Valkyrja I, Strike The Blood Wiki