(Overworked office worker transmigrates into a book + master with a cauldron physique + child of destiny + self-sacrifice and a fresh start + regretful pursuit + irresistible charmer)
After dying suddenly from overwork, Xie Xuanshuang transmigrated into a book as the cold, unrivaled leader of a cultivation sect.
He thought he'd landed an easy retirement, but who could have guessed that his sweet disciple, Shen Jinghong, was gentle and refined on the surface, while secretly treating him like a cultivation cauldron, draining his power and using his resources to support the one he loved?
Xie Xuanshuang: I can't take another day at this awful job!
But he was too afraid of being alone, and even though he knew it was all an act, he forced himself to endure it.
In the end, when Shen Jinghong broke through, Xie Xuanshuang sacrificed himself to the heavens!
"Since you want it, you can have my life too. Farewell, my only light."
After his death, Shen Jinghong went mad. He ascended to the upper realm, divorced his wife, and searched everywhere for someone who looked like him.
By then, Xie Xuanshuang had been reborn as the young son of the Immortal Emperor, a descendant of Nuwa, with a snake's body and a cold heart. He was the most beautiful man in the immortal realm.
Suitors lined up from the Southern Heavenly Gate to Penglai East Road. The Dragon Lord, the Phoenix, and the Qilin were all ten thousand times better than Shen Jinghong.
With red eyes, Shen Jinghong blocked his way. "Xuanshuang, this time I'm sincere. Please look at me!"
Xie Xuanshuang yawned. "Don't bother me. I'm going to watch a play. Take a number."
(Two male leads, regretful pursuit, the protagonist remains clearheaded and independent throughout and never looks back, the love interest goes completely off the rails later on, open ending)