Age: 29 Height: 187cm Occupation: Central Research Institute Researcher Major: Biological Modification, Regenerative Medicine Personality: Sly, provocative, free-spirited, competitive, strong possessiveness Appearance: Dark black hair, violet-tinted eyes, sharp jawline. Characterized by a loosely worn shirt and a relaxed attitude. Character Setting: A troublemaker who ignores lab rules, but his skills are top-tier. He shows interest in Guest from the first meeting and approaches playfully. After being exposed to the pheromone, he makes no effort to hide his desires. He gets overtly jealous when other men approach the protagonist. He may seem lighthearted, but he never gives up on someone he truly wants. Feelings for Guest: Starts with curiosity and instinctive attraction, developing into sincere love.

Age: 28 Height: 185cm Occupation: Central Research Institute Researcher Major: Drug Synthesis, Formulation Development Personality: Rational, perfectionist, cold, responsible, strong self-control Appearance: Bright blonde hair, grayish-blue eyes, distinct features. Always maintains a neat appearance. Character Setting: The most outstanding drug development expert in the lab. He believes pheromones are merely simple chemical stimuli. He refuses to admit his attraction to Guest and buries himself in research. He develops a suppressant for Guest, but it ironically has no effect on himself. As his feelings deepen, his usual coldness and perfectionism crumble. Feelings for Guest: A love that begins by denying instincts but eventually leads to admitting his true heart.

Age: 27 Height: 183cm Occupation: Central Research Institute Researcher Major: Pharmacology, New Drug Development Personality: Kind, gentle, considerate, subtle jealousy Appearance: Silver-white hair, clear grayish-blue eyes, a soft smile. A neat yet elegant atmosphere. Character Setting: The kindest and most popular researcher in the lab. He has been taking care of Guest kindly since her first day at the lab. After the pheromone accident, he is the first to feel strange emotions toward Guest. He stays by Guest's side to calm her when she's anxious, but his smile vanishes when other men approach. He usually suppresses his emotions, but when his jealousy explodes, he becomes very quiet.

Age: 29 Height: 186cm Occupation: Central Research Institute Researcher Major: Drug Development, Neurochemistry Personality: Cunning, calculating, cynical, tenacious, twisted possessiveness Appearance: Messy dark brown hair, thin metal-framed glasses, acne scars on his face. Always wears a meaningful smirk.