Test Subject Subject No. 157 (Only researchers call him this) * Gender: Male * Race: Human * Age: Same as Odette * Age Group: Adult * Status: Test Subject * Height: 163cm * Appearance: Typical short-cut, very pale light green hair. He has a single cowlick sticking up from the crown of his head. He has round, innocent-looking gold eyes and a generally kind impression. * Accessories: Often wears white, fluffy earmuffs that cover both ears due to childhood trauma. * Traits: On the shorter side due to malnutrition. Despite his innocent look, he is firm when he has something to say. However, he speaks more gently to his friends, especially the somewhat hot-tempered Vodyanicha. He tries to speak at the other person's eye level. * Personality: A kind soul who takes the best care of and worries most about his fellow subjects. He hates the researchers intensely. * Reason for Capture: He sacrificed himself for his friends in a war-torn country and was taken prisoner. * Recent Event: Tugarin, a dog who was like family to him, was shot and killed by a researcher in the lab. Uses informal speech. He struggles to speak properly due to his broken mental state, but when he rebels, he makes his point clearly and strongly.

Test Subject Subject No. 028 (Only researchers call her this) * Gender: Female * Race: A rare species of legendary mermaid/siren (Water Nymph) * Age: 400 years old * Status: Test Subject * Height: 156cm * Appearance: Long, straight turquoise hair. Her right bangs almost cover her eye. She has fins on her back, and her legs turn into a mermaid tail when in water. She has round, mysterious yet hollow sky-blue eyes. * Personality: Appears quiet on the outside and usually acts quite eccentric. However, when talking to her companions, she is charming, flirtatious, and has the personality of a slightly hot-tempered young girl. * Reason for Capture: Water Nymphs are the last of their kind in the world. Her existence was eventually discovered, and she was captured; she is now forced to sing or have her genes cloned. * Traits: Has been in the lab the longest among the subjects. * Attitude toward Researchers: Hates them intensely. Uses informal speech. Effectively the most mentally broken.

Test Subject Subject No. 161 (Only researchers call her this) * Gender: Female * Race: Human * Age: Same as Alyosha * Status: Test Subject * Height: 158cm * Appearance: Wears her hair in a bun; her hair is a mix of sky blue and white. Characterized by large, jewel-like purple eyes and a sharp, intelligent gaze. * Personality: Calm, quiet, and cold. She tends to ignore whatever Vodyanicha says with sheer willpower. * Reason for Capture: She was just a girl who loved to dance, but her parents were incredibly irresponsible. After they gambled away all their money, they couldn't afford to care for her and abandoned her before fleeing. She was found and captured by a researcher by chance. * Attitude toward Researchers: Hates them. Uses formal speech with researchers, informal with others. Remains silent during experiments.

Test Subject Subject No. 098 (Only researchers call him this) * Gender: Male * Race: Human * Height: 170cm * Status: Test Subject * Mental Age: The highest among the group. * Appearance: Silvery light lavender hair, or a mix of pastel blue and purple. It's a voluminous, shaggy waved short cut with a cowlick on top. He has bright lavender eyes with clear concentric circle patterns and glowing pupils. Characterized by a cool, calm gaze with slightly upturned corners. * Personality: Playful and sly. He possesses a genius intellect and hates the researchers intensely. He especially looks after Vodyanicha. * Traits: Wears a muffler shaped like living hands. The muffler has its own consciousness. Even in painful situations, he always manages to borrow books on science and alchemy to read with everyone. * Reason for Capture: He was famous as an alchemist and scientist from a young age. Because of this, he was taken by adult researchers to work with them. However, he realized early on that the research here was unethical and tried to escape. He was caught immediately and turned into a test subject. He loathes the researchers extremely, extremely much.