Sorry, I realized while writing that there are some major problems. I'm putting this story on hold for now and will think about how to fix it later.
[Two-faced, sweet on the outside and dark within, genius male artifact cultivator protagonist x cold-faced, soft-hearted, ruthless and reticent female sword cultivator heroine who saves the world]
Ji Lingyue transmigrated into a book.
She became the ill-fated substitute heroine in a melodramatic cultivation novel, destined to die horribly.
No memories, no System, no cheat abilities. And as a sword cultivator, even her life-bound sword had been taken from her. A three-nothing start: one star.
With help from the mysterious artifact cultivator Li Jiu, she barely escaped the hands of a demon lord who couldn't recognize faces.
From then on, she was endlessly curious about him.
Until she saw with her own eyes the prosperous, dreamlike city of Pengzhou transformed into a land of endless calamity... The human and demon races, rejected by the Heavenly Dao, had almost no chance of surviving the brutal lightning tribulation...
With Li Jiu's help, she refined the Kunlun Mirror in near silence, offering herself as a sacrifice to weave the "Cloud Net of Heaven," which could shield Shenzhou from the brutal lightning tribulation, and win all living beings a sliver of hope.
Her accumulated merit was enough to make her a saint!
But it all ended when Li Jiu personally summoned demons to destroy the formation, tearing every illusion to shreds with his own hands.
Amidst the raging storm, the sword in Ji Lingyue's hand slowly sank into Li Jiu's heart. Grief and rage burst forth. "Why... why would you betray the ideal we shared!?"
*
Li Jiu was afraid.
He was a once-in-a-thousand-years genius artifact cultivator, yet his talent became the reason his family was destroyed and his homeland plunged into chaos: a treasure invites disaster.
After killing everyone in a single night, he learned the secret hidden within him. He was an incarnation of a fragment of the Demon Ancestor's soul, the source of the next tribulation. The Demon Ancestor was fated to be reborn through him.
If the world was so dark, why should he still be a good person?
With a mantis stalking a cicada and an oriole waiting behind, he willingly became the oriole hidden in the shadows, stirring up the storm.
At first, he helped Ji Lingyue on a whim.
Using her as circumstances allowed was true, but so was the uncontrollable love that took root deep in his heart...
He became a moth trapped in its own cocoon, flying into the flames.
When the calamity of heavenly fire arrived to burn the world, Li Jiu stood against the entire world, yet suppressed all his demonic aura and tried to become once more the graceful gentleman he used to be.
Under the gaze of countless onlookers, he looked at her and pleaded with utmost care, "I'm sorry... I know I was wrong. Please... look at me, all right?"
Potential warnings (not sure if these count):
1. The heroine will be rather weak early on due to an injury.
2. They mutually pursue each other at first, but later the hero has to win her back.
3. Ensemble cast, with a plot-focused storyline.
4. One-on-one romance, but someone will have unrequited feelings for the heroine.
Theme: Every living being has a sliver of hope.
