Death March kara Hajimaru Isekai Kyusoukyoku (WN) - Side Story: Kishresgalza Clan

Li Yi accidentally obtained a black science and technology library, which contains countless books of the inheritance of high-tech civilization and records countless knowledge.

There are thousands of bells in the book, there is a golden house in the book, there are many horses in the book, and there are Yan Ruyu in the book.

Li Yi has completely turned into a bookworm, learning all kinds of knowledge from the library, grand unified theory, particle Tebo theory, …, acquiring various black technologies, superconducting materials, super batteries, intelligent algorithms, … .

- Description from novelbuddy

I was transmigrated into a work I liked and finally came back.But after, I was dragged into an Academy Romance Novel, which I skipped over after only reading the prologue.There I found a half-broken possessors who regressed endlessly.

The Spirit Blade Sect was founded in the year 4233. After thousands of years of producing first rate Xiuxian geniuses, it had become one of the five biggest sects in the Ten Thousand Celestial Alliance. The head elder, Immortal Feng Yin is one of the seven Executive Elders of the Ten Thousand Celestial Alliance, with a cultivation that can shake the whole world. The Spirit Blade Sect is dedicated to peaceful development, and holds the core values of Truthfulness, Kindness and Loyalty. In order to expand the sect and bring in new blood, all heroes and geniuses have been welcomed to attend the Celestial Gathering.

What would you say is the most valuable thing in this world?