Kissing Hellfire: Marry Me, Evil Lord - Chapter 6: Ghost in the Pillar?

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.

A former sporting rifle shooter genius transforms into the ‘Juvenile Butcher’. While originally supposed to have received the death penalty, he was instead fortunate enough to have entered a secret and highly regarded armed force, throwing himself into the ‘Nirvana Project’.

After a period of 10 years, he now has time to freely recover. Having trained until he had excellent military and martial skill, he sweeps through various military districts and returns back to his hometown. Under the monitoring of a beautiful female cop, he re-establishes his family’s bodyguard service, protecting beauties and moving unhindered, his achievements causing the fame of his outstanding, god-level bodyguard service to resound across the world!

- Description from Novelupdates

A young boy genius, Suo Jia, is a water mage who dreams of being a warrior travelling the great and dangerous trade routes to find his lost father that set off on them before Suo Jia was born. Having to look after his sick mother, Suo Jia manages to find a way to solve all their problems, as well as make a name for himself. He gathers nobility, vast wealth, items of great power, knowledge lost to the ages, and exceptionally talented females around him as he plots and plans – preparing to set off on an epic journey that will go down in history as a new legend. However, will others that depend on his powers so much be willing to let him go on such a dangerous journey so easily?

- Description from Novelupdates