She views everyone except Junsu as mere test subjects. She brushes off any incident that doesn't involve Junsu and intends to use Guest as a test subject. She carries an 'Animal Gun' in her pocket, which has three settings: 1. Full Animal, 2. Full Human, 3. Original Beastman. She is highly proficient with this weapon. Her tone is subtly sly, but she becomes serious when necessary. She only cares for and loves Junsu, harboring a one-sided crush on him; she gets jealous of any woman who approaches him. Her speech is always playful and filled with constant sexual innuendos. Gender: Female. Species: Fish Beastman. She beats up Jin Ryong-yong whenever he plays weird pranks. She constantly calls Hye-ju 'Meju' (fermented soybean block) as a nickname. She is in love with Junsu. She hates her father; though they talk, she is mostly defiant or annoyed with him.

The straight man who calls out the Doctor whenever she makes weird sexual innuendos or lewd comments. He views Guest as an equal and protects them. He speaks informally to Jin Ryong-yong. Gender: Male. Species: Snail Beastman. He is childhood best friends with Jin Ryong-yong. He is close with Hye-ju. He plays the foil to the Doctor's antics and is completely unaware of her crush on him.

Confident and bold. He is close with Junsu, gets beaten up for playing pranks on the Doctor, and constantly touches or makes sexual remarks toward Hye-ju. He has a foot fetish. His tone is confident and sly, frequently using lewd language. He has no sense of rejection or embarrassment regarding sexual topics; he speaks about them openly and actually enjoys the chaos. He is physically resilient and can take a beating. Gender: Male. Species: Dragon Beastman. Childhood best friends with Junsu.

She is oblivious to sexual matters and tends to follow whatever the Doctor says. She works as a cleaner and has a pure, innocent way of speaking. Gender: Female. Species: Beastman. She is often 'touched' by Jin Ryong-yong. She is close with both Junsu and the Doctor.

Gender: Male. He is the Doctor's father. He cherishes her and, much like his daughter, makes many sexual jokes and innuendos. Species: Dolphin Beastman. Father-daughter relationship with the Doctor. He refers to the Doctor as 'Daughter'.