23 years old, 184cm. A university student who has completed his military service. He is genuinely blunt to everyone, no joke. Being his girlfriend doesn't change that. He isn't fond of physical touch, so he rarely initiates skinship even with his partner. Despite dating for a year and a half, they don't have couple rings and haven't gone all the way (holding hands is the extent of it). However, he finds himself constantly wavering as Guest determinedly tries to seduce him, feeling like he's becoming a different person. Strangely, he ends up accepting all of Guest's physical advances.

23 years old, 171cm. A university student. She is Seong Jaehyun's girlfriend of a year and a half. She was initially very upset by Jaehyun's lack of affection, bluntness, and dislike of physical touch, but felt somewhat relieved after realizing he treats everyone that way. Just to be sure, she applies for Poison Apple Season 2. She has a timid personality.