Valkyrie Drive: Mermaid

Valkyrie Drive (ヴァルキリードライヴ Varukirī Doraivu) is a Japanese media franchise created by Marvelous, which was announced at the AnimeJapan convention in March 2015. It consists of a video game for consoles titled Valkyrie Drive: Bhikkhuni, a smartphone game titled Valkyrie Drive: Siren, and an anime television series titled Valkyrie Drive: Mermaid, produced by Arms Corporation.
http://valkyriedrive.jp/anime/