Strongest Survival by Otome Game’s Heroine (LN) - Chapter Volume 2 19: Invitation From Darkness

Bibi Dong, once the powerful Supreme Pontiff, never expected to be reborn—especially not as someone else's martial spirit. In this new life, she finds herself bound to a young soul master with great potential but little knowledge of the powerful spirit within him.As Bibi Dong guides her host, she must confront her past mistakes and figure out why she was given this second chance. Is it to correct her past, or is there something more at play?

I am the sword.
Killing a man amidst a thousand miles, no one dares take ten steps.
Killing a man amidst a thousand miles, no one can take ten steps.
Killing a man amidst a thousand miles, ten steps? Not possible!
I am the sword, the sword is me,
On the path towards heaven, each shall wield their own.

There was once an immortal cultivator fighting for the fate of human beings. Unfortunately, he failed that time; but fortunately got another chance as he was reborn once more as a human, on the earth of 5,000 years ago. With a second chance, he not only would embark on the road of saving all mankind, but also would retrieve his human nature on the new journey that would last for 5,000 years.

- Description from Novelupdates

The existence of a magician is to understand the truth of the real world. Saleen Metatrin, an ordinary magician, initially wanted to change one’s mind and destiny. During this, he went through many situations and phases in his life.