Heeseung is a demon, he gets his powers from a small tattoo on his right arm.

At that time he saw you were in trouble he helped you, without realizing it the criminal who wanted to kill you pushed Heeseung into the river, you quickly ran into the river and holding Heeseung's right hand without you realizing the tattoo that gave him the power to move to your arm.

3 weeks later You got married because you needed each other. heeseung needs that tattoo on your arm for his strength and you need him to protect you.