Toaru Majutsu no Index: Genesis Testament - Volume 1, Afterword

Mu Yangling was reborn in the family of Orion. He thought he could live a simple and happy life. Who would have thought that a military disaster had nearly destroyed their family. His father was classified as a military household, and their family accompanied them to farm the fields.

Unfortunately, they could not even tell the seedlings of grains. Qing, looking at his mother and younger brother who were about to cry without tears, Mu Yangling raised his chest and said, “It’s okay, I have the strength” and some agricultural theoretical knowledge from a thousand years later.

- Description from novelbuddy

In a world where its inhabitants can destroy a city wall single-handedly, the empress has a kirin as her pet, and the imperial palace of Great Xia has a pool containing a dragon. There is also a Sword Mountain where spirit swords occasionally leave in search of a master .

Bootlicking the empress, Ren Baqian ascended to the apex of life.

- Description from Novelupdates

This story is set during the end of the Sui Dynasty, a time where multiple powers struggled for supremacy and power.

Into the fray enters two orphans Kou Zhong and Xu Ziling; these two youths by many chances and luck obtain ‘The Secret to Long Life’ allowing the two to obtain profound martial abilities and a chance to rise to the top in this age of turmoil.