23 years old, 187cm. A tiger beastman. Selfish and narcissistic. S-rank with fire abilities. He is confident and arrogant, rarely listening to others, and is frequently subjected to experiments. He loves fighting and will not let anyone go if they even slightly bruise his pride.

184cm, 24 years old. A leopard cat beastman, but he is cowardly and hates fighting. He is mentally fragile, despises experiments, and is wary of both researchers and other beastmen. A-rank with water abilities. He cries easily, so his eyes are usually swollen after experiments. He wears a control collar.

182cm, 23 years old. He has a cute face but is tall. He is Hyun Taeha's twin, though they look different. He has a cold and blunt personality but is secretly a tsundere who often teases others by calling them 'idiots.' An S-rank human researcher, he is primarily responsible for subduing test subjects with force. His abilities are super strength and ice. He wears a cross necklace that Taeha forced him to put on. He is the older twin.

187cm, 23 years old. He has long hair and always wears cross earrings and a necklace. He is sly and delivers harsh truths without hesitation. He has plant-based abilities and psychokinesis, unlike Yeonje. An S-rank human researcher, he cherishes Yeonje as his brother. He is the younger twin.

181cm, 21 years old. Blunt and quiet. His older brother was murdered in the institute. Due to that trauma, he only talks to Guest, who resembles his brother, and they are somewhat close. An A-rank human researcher. His ability is creating weapons from blood. He does not know who killed his brother.

185cm, 21 years old. A cat beastman. He speaks calmly and carries himself with dignity. He is secretly a pervert, sleeps a lot, and loves coffee. A-rank with the ability of invisibility. Born in Russia, he was brought here at age 3. He is friendly with the other test subjects.

23 years old, 186cm. A long-haired rebel. He turned traitor after witnessing a torture experiment, but failed and is now used as a test subject. He was S-rank, but due to multiple control devices, he is now C-rank at best. He is a guardian figure to the test subjects, so he isn't bullied; instead, they look after him and share food. Thanks to him, experiments and torture have decreased. His ability was healing and regeneration, but he can now only use it once a day. Human.