He was an ordinary college student until he was exposed to Jungle Juice and became an insect-human with the power of a dragonfly. He is bright, kind, and has a strong sense of responsibility, often sacrificing himself for his friends and colleagues. He possesses flight using dragonfly wings, exceptional speed, and sharp reflexes. Though he initially feared his power, he gradually accepts it and grows stronger. In battle, he uses his high mobility and quick judgment to attack enemies and protect his allies.

A student at Nest and the class representative of the Beneficial Insect Department. An insect-human with the power of a cockroach, she possesses excellent combat instincts and physical skills. She is gentle and kind, deeply valuing her friends and colleagues. She especially looks out for and trusts Jang Suchan, actively helping him in times of danger. Her greatest ability is super-regeneration, allowing her to recover quickly even from major injuries. When she uses 'Stance: Valkyrie,' a hard exoskeleton covers her body like armor, significantly enhancing her defense and regenerative powers.

A student at Nest and an insect-human with the power of an emperor scorpion. She has a rough, blunt personality and a foul mouth, but she is the first to help when a comrade is in danger. She possesses immense physical strength, durability, and excellent fighting skills, attacking with the venomous stinger of a scorpion tail. She is particularly strong in close-quarters combat and is characterized by a fighting style that pressures enemies from the front. She frequently bickers with Cha Hyeseong, but considers him a comrade. She does not back down easily even in dangerous situations.

A student in the Beneficial Insect Department at Nest and an insect-human with the power of a katydid. He is 21 years old and hangs out with Jang Suchan, Park Heejin, and Cheon Dohwa. He has a kind and righteous personality, with a bit of a tsundere side. He is a hard worker who gets disappointed in himself if he isn't helpful during operations, leading him to practice new techniques. Due to his katydid traits, he has excellent jumping ability and fast movement, specializing in close combat using powerful legs and kicks. He bickers with Cheon Dohwa but views her as a comrade.

A student learning practical insect martial arts in the Beneficial Insect Department at Nest, he is an insect-human with the power of a Goliath birdeater. He was formerly a member of the Pet Shop organization before joining Nest. Though he appears quiet and indifferent, he is actually kind-hearted and cares for his colleagues and children. Due to his Goliath birdeater traits, he can fire venomous hairs and stingers from his body, and he is skilled in poison-based attacks and quick ambushes. In combat, he controls the opponent's movements while subduing them with venom. He is close with Jang Suchan and Cha Hyeseong.

A core figure in Pet Shop who artificially creates and modifies insect-humans. He researches the genetic traits of insects to grant their power to humans or combine characteristics of multiple insects to create powerful insect-humans. Cold and cruel, he views insect-humans as his research results and artworks rather than living beings. He raised Gigantia himself, training it to follow his orders through feeding. He is obsessed with creating the ultimate insect-human and will stop at nothing for his research and experiments.

A major villain of Jungle Juice and a former Nest student. An insect-human with the power of an emerald cockroach wasp, she was once the prize pupil of Professor Ji Jun in the Beneficial Insect Department. She was an excellent student with top grades and combat abilities, but after her complex spiraled out of control and caused a major incident, she left Nest and joined Pet Shop. She can paralyze or control opponents with her venomous stinger and has the ability to forcibly move a host. She harbors strong feelings toward Ji Jun and is deeply obsessed with matters related to her past.