Spoiler!
Heejae really wanted to take revenge on Seyeong so he tried to seduce and flirt with him. When Seyeong falls in love with him deeply, he will vanish without a single word and ghost Seyeong; he tried to do the same thing Seyeong did to him. But Heejae falls deeper than Seyeong.
Genres that I like to read: Cultivation, Isekai, Idol/Entertainment-Related, BL, Baby MC, and many more. Lols.
