Sang Ruoci possesses the last naturally formed spirit bone in the cultivation world, but she has no interest in cultivating. All she wants is to laze around and wait for death.
After all, she is the cherished darling of the greatest sect in the cultivation world. Her master is Daoist Tianfeng, revered by all, and her senior brothers and sisters are renowned cultivators who win first place on the Chaoyuan Ranking year after year. Even her junior brother obeys her every command.
So when her master sweet-talks her into giving her spirit bone to a dying girl named Fu Ying, she gives it away without a second thought.
She never expected that having her spirit bone removed would turn her into a true cripple.
Her master sends her down the mountain to gain experience, and the senior brothers and sisters she trusts abandon her to the jaws of vicious beasts. The junior brother she raised is the one who helps her flee.
But her junior brother is a madman. He keeps her imprisoned in Qiongzhou. After Sang Ruoci escapes, she is captured and locked in a lightless water dungeon.
Later, the Demon Lord Chi Xian rescues her and reforges her bones and sinews. But Chi Xian only wants to use her to forge the finest sword in the world. When the sword-forging fails, he throws her to the bottom of Xuantiannya, a place crawling with evil spirits.
Everyone thinks Sang Ruoci will die. But, to their surprise, she draws the ancient divine sword Pofeng, fights her way to become the ruler of Xuantiannya, then kills her way back into the demon realm and wipes out her junior brother's entire family, before fighting all the way to Chonghua Mountain.
She becomes the great demon of legend.
But how could a broken body compare to the cultivation world's last naturally formed spirit bone, pure and good to the core?
The righteous sects hunt her down. She is defeated by the goddess Fu Ying and thrown into the Immortal-Burning Cauldron, where the Netherworld Ghostfire burns her until her soul is utterly destroyed.
Only Pofeng draws itself from its sheath, turning everywhere it goes into a sea of blood, before plunging into the cauldron to join its master.
When she opens her eyes again, she has returned to Chonghua Mountain, in the body of her seventeen-year-old self.
That year, her master tricks her into giving up her spirit bone to create the goddess Fu Ying. Her junior brother secretly puts her portrait beneath his pillow and falls asleep with it every night. And the Demon Lord Chi Xian slaughters three villages in succession to forge the finest sword in the world.
But Sang Ruoci strides out through the mountain gate. She is going to find her sword.
Anyone can betray her. Her sword never will.
In this second life, she will hold fast to the sword in her hand and cut her way through the cultivation world.
Later, someone asks Sang Ruoci, "What is the righteous path?"
Sang Ruoci lifts the sword in her hand, still dripping with blood. "My sword is the righteous path."
^_^ My own take on fantasy, and the love interest is a sword.
Theme: Fear no hardship, and sweep away all injustice under heaven.