Hero Oniichan to Last Boss Imouto: Bakken! Seikenzer

The hero comedy story follows the Tsurugi twins: Kanato the older brother and Minato the younger sister. Minato had returned from studying abroad, and the pair go to a local event. Kanato draws a "holy sword" and summons the mysterious knight team Blood Temple. Kanato sets out to bring his sister under control after she seems to become a force for evil. Kanato refuses to yield in battle, and the transformed siblings face off.

(Source: Anime News Network)