Why Not Make Both Twins 'Girlfriends'? - Chapter 4Volume 1 .1 - Trying to Unravel...?

Mo Ran felt that taking Chu Wanning as his master was a mistake.

A wonder falling down from heaven! A boy possessed by strange blood! Gods tremble! Demons flee! A boy from the land of Dong Zhou. A pink skull as his sworn friend until death. A story of a determined warrior struggling for power. A legend that shakes the galaxy and disturbs the worlds of god, demon and man.

- Description from Novelupdates

Side story of Kyoukai Senjou no Horizon bundled with the first press release of the 1st, 3rd, 5th and 7th Blu-ray volumes of both seasons of anime.

This side story follows Asama, Kimi and Mitotsudaira aboard Musashi one year before the beginning of the main story, as Asama is considering to create a music band together with her two friends for the next festival in Aki, a territory under the governance of K.P.A. Italia.

After successfully reaching the Core Formation Stage and forming his Golden Core, Bai Langtian was betrayed by his own Master. His core was ripped from his body, and he was thrown off a mountain cliff into a valley full of demonic beasts.Thankfully, he survived the fall, and met his senior sister, Shangguan Yue Ling.She too had been betrayed by the same Master and pushed into this valley ten years ago. Ever since, she had been surviving alone by eating the corrupted flesh of demonic beasts.Now, Yue Ling revealed to Langtian a new path of cultivation:Demonic Cultivation.To reclaim his strength and take revenge, he must consume the flesh and essence of ten thousand demonic beasts.