Am I Not the White Moonlight's Stand-In? [Book Transmigration]

Luo Bai transmigrates into a cultivation novel as a cannon-fodder character. The greatest person in the world is named Lin Xuan.

System: Lin Xuan is only one tribulation of love away from ascension. You must play his deceased beloved, make him fall in love with you, and then let him kill you. That will help him resolve his heart's knot and ascend to immortality.

"..." Luo Bai looks at his own face. He bears a nine-out-of-ten resemblance to the old rival Lin Xuan once killed with a single sword thrust.

Great. I'm supposed to play the beloved while wearing my old rival's face? What's the point? He'll kill me the moment he sees me!

System: No, you have to make him fall in love with you first. Otherwise, your soul will be annihilated!

No one knows what Sect Master Lin's deceased beloved looked like. Luo Bai follows the clues in the book to make himself a fake face, joins Lin Xuan's sect, and does his best to be the cold, aloof master's thoughtful little disciple.

Luo Bai: Master, Master, look at the white jade statue I had made for you at great expense. It's bigger than the other Grandmasters' statues!

Luo Bai: That demon dared to say you're all reputation and no substance, the greatest in the Three Realms. I'll make him beg for mercy, even if it costs me my life!

Luo Bai: Master, Master, I made you a robe myself. It's snowy white, perfect for your celestial bearing!

Fellow disciples: ... It's not like the greatest sect in the world is short on money. Why spend a fortune on a statue?! That demon is no match for even one of our sect leader's fingers. Why would you risk your life?! And the sect leader has thousands of fine robes. Why would he need you to... Wait, did the sect leader just smile?!

Lin Xuan, the greatest man in the world, is aloof and cold-hearted. The only person he favors is an unremarkable young disciple, making everyone else envious and jealous.

But one day, the young disciple's attitude changes completely. He goes around praising the old rival Lin Xuan pierced through the heart with a single sword as a paragon of virtue, someone worthy of admiration. He even claims he joined Lin Xuan's sect to avenge that rival.

Luo Bai weeps as he walks the path of courting death, but no matter how long he waits, Lin Xuan still doesn't kill him. If anything, he treats him with even greater care.

Come on, if you don't kill me soon, my soul is going to be annihilated!

Luo Bai figures he may have gone too far with playing the beloved, so he decides to tear off his mask once and for all.

Now you'll finally kill me, right?!

Luo Bai closes his eyes, waiting for a sword through the heart. The next moment, Lin Xuan pulls him into his arms.

"I've regretted it for so many years." Lin Xuan's voice is hoarse with a restraint Luo Bai has never heard before.

Luo Bai freezes, then blinks. "Regretted what?"

"Not slaughtering every sect in the cultivation world to bury them with you."

Luo Bai: ... Huh?!

One-on-one romance, mutual devotion, the love interest has a secret identity, and the protagonist has even more secret identities than him without realizing it.

Theme: True love above all.