Sono Mukou no Mukougawa

The story is about Kudo Futaba, a young boy who is pulled into a strange world when he rescues a girl named Kiara, a powerful girl whom many people wish to capture or kill. Futaba pledges to protect Kiara from her pursuers and help her find her missing master.

This short animation clip was released as part of the special Comic Blade Digital DVD sold at Animate.

(Source: AniDB)