The Martial God who Regressed Back to Level 2 - Chapter 666:

In the far future humanity is threatened by monstrous beings called kaiju now humans have expanded across the galaxy with the development of new techniques and fleets of mechs.Alto a young boy with dreams of becoming a great mech pilot is forced to be a mech designer. He finds a strange technology that opens his eyes to the vast secrets of the galaxy, now with a new purpose Alto must become something the world has never seen before.A/N: Just wanna do a good sci-fi book

The protagonist, Winnie (文尼), confesses his love to his childhood friend—the princess he’s been secretly in love with for years—but is brutally rejected in public. His heart shatters, he’s humiliated and ridiculed, and he collapses unconscious. When he wakes up, he vaguely remembers his past life’s memories and realizes he has transmigrated into the world of an otome game he played before. At first, he’s thrilled, thinking, “Nice! I must have been reincarnated as a villainous side character who disrupts the protagonist’s romance, right?” But then… surprise! He’s not just the villain—he’s the “Saintess”!

Chen Sha came to a world of immortal martial arts and was ordered to take charge of the world’s first sect.

Before his death, the previous chief told him:

“If you don’t become the best in the world for one day, you are not allowed to go down the mountain for one day.”

So he closed himself in painstakingly, crossed the heaven gate in his body, and faced off against the ancient and modern powerhouses…

…

Many years later, Chen Sha recalled the day he went down the mountain,

From the moment he descended the mountain, he was number one in the world.

In the next ten epochs, any gods and demons have returned, immortals and Buddhas have lived in the world, ancient powers and ancient gods have appeared one after another.

No matter how the times change, he has always been No. 1 in the world and has never changed.

- Description from novelbuddy