Valkyrie Drive: Mermaid

Tokonome Mamori is relocated to Mermaid, an isolated island housing individuals with extraordinary abilities. After an assault, Mamori is rescued by Mirei, a recent arrival. Their attackers continue their pursuit, forcing the pair into a desperate situation. At a critical moment, Mirei kisses Mamori, causing her to transform into a weapon. Mirei then uses Mamori in combat to fight back against the assailants.