Valkyrie Drive: Mermaid (2015)

Tokonome Mamori arrives at Mermaid, a quarantine island designed for individuals with extraordinary abilities. Shortly after her arrival, she finds herself under attack, but is rescued by Mirei, another new arrival. As they face relentless foes, their situation grows desperate. In a surprising twist, Mirei kisses Mamori, transforming her into a powerful sword. Armed with this new weapon, Mirei prepares to fight back against their attackers, turning the tide in their favor.