It was officially announced at the Dengeki Game Festival 2015 event that Strike the Blood will be getting a two-episode OVA series to be released at the end of 2015. The OVA will be an original story written by Gakuto Mikumo.

In order to uncover the "end of the sky," as spoken of in ancient mythology, Kal-el Albus is sent to Isla, an island in the sky. There he attends Cadoques High's Aerial Division, where he enjoys a carefree life with his schoolmates. That is...until a surprise attack by the air tribe drags Isla into a bloody war. (Source: NIS America)

OVAs bundled with the 15-17th volumes of the Mushibugyou manga.

An extended version of the second season's first episode, which is under the same title.