Princess Xiaoyanzi's Bodyguard Ertai

[Yandere + seductive schemer + secret guard rises to power]

Princess Xiaoyanzi is to be married off to a sickly prince.

Her secret guard, Ertai, looks gentle and harmless. He speaks softly and, when kneeling before her, is as obedient as a dog.

When she climbs walls, he catches her. When she gets into trouble, he cleans up after her. If she wants the stars, he’ll bring her a ladder.

She thinks he’s simply a loyal servant.

Until she is struck by a deadly poison no one can cure. He returns covered in blood, feeds her the antidote, then cuts open his own wrist and lets his blood drip onto her lips.

“Princess, the antidote needs the blood of a living person as its catalyst.”

“From now on, your veins will carry the same blood as mine. I gave you your life. We’ll never be apart again.”

Only then does she realize that all along, she was the prey.

[Female Alpha, male Omega, but he’s actually Alpha to the core]