Jaywalker_Holmes

Ren, a modern doctor and a secret master magician, suddenly finds himself inside a random book he picked up at the airport...as the villainous older brother of the protagonist. As the bad guy, he's supposed to make life difficult for the Male Lead until the latter grows up and kills him in revenge. However, looking at the broken teenager in front of him, Ren can't help but feel his heart soften. 
Fang was an orphan who had never known what a family is. Abandoned at birth, all he knew was pain and fear. He loved nothing, and wanted nothing...until he saw the angelic Wade. To save Wade, Fang didn't hesitate to sacrifice himself. ..after all, there was no one to cry over him.
But then, Ren appeared and turned his world upside down.

The Villain Saves the Male Lead

"Are you feeling better now?" Ren asked softly, rubbing Fang's back with gentle fingers once the younger man was finally done crying.

Fang gave him a bitter smile. "I'm sorry, I should be the one who should ask you that...I'm so useless."

Ren pulled him closer and kissed his brow. "Don't day that, my little darling. You're the most amazing person I know."

Fang was silent for a moment. Then, in a clear attempt to divert the conversation into another direction, he muttered, "I'm almost as tall as you now."

Ren let him shift the topic away and smiled indulgently. "When you're taller than me, should I call you my big darling?" he asked teasingly.

"Maybe I'll call you my little love instead," Fang murmured.

"I'll look forward to that," Ren said, kissing his boyfriend's cheek again.

The boy was just too adorable, Ren thought.

60 - Side Effects?