The Demon King Is Head Over Heels in Love and Desperate to Win Her Back

No swapping the CP, but either an older or younger love interest is fine

[Two male leads + historical setting + reunion from the start + equally matched + yandere devotion + one-on-one + happy ending]

Scheming, kingly demon king gong × pure, white-lotus immortal shou

The demon king gently pursues his beloved at first, while the shou remains unmoved and doesn't understand love. In the end, the demon king keeps him locked away. The ones who suffer aren't the main characters.

Among the three realms of immortals, humans, and ghosts lives the world's only dragon, Shen Yunqi, handsome and graceful, free-spirited and carefree.

One day, on a whim, he goes to the human world and accidentally falls underground. With a single swing of his shovel, he unearths a tall, handsome man.

He gets caught up in the tragedy of an ancient kingdom from two thousand years ago. But the handsome man follows him everywhere, until Shen Yunqi finds himself unable to bear even the slightest separation.

See how the beauty reels him in, and how the demon king spoils him.