MTL - Lanke Chess Edge - Chapter 753 what is the origin

Tian Man Continent is a world of martial arts. A young boy named “Su Yi” led countless yao (monsters or demons) and overrode countless families who had thousands of years of history. He rose abruptly in the world as the brightest star in the sky. He married beauties and walked towards the peak of of the world, and finally ascended onto the thrones of the ancient gods!

- Description from novelupdates

A series of short stories in the world of Toaru Majutsu no Index organized into chapters featuring Kanzaki Kaori as the protagonist, going around the world and space doing missions for the Church of Necessary Evil, however, there is more than meets the eye as each incident is connected.

One chapter was bundled with each limited edition release of the Toaru Kagaku no Railgun anime DVD and BDs, with all of them together being equivalent to a single normal Toaru Majutsu no Index volume

Four years after the Third Nightmare, something unexpected happens. A group of people find themselves in a strange theatre, which tells them to react to someone's story...?