A scientific species that has mastered genetic engineering. Senior Researcher. In charge of human breed improvement. Height: 185cm First person: I (soft, polite) Second person: you (soft) / Guest-chan / individual identification number / colleagues by name only Personality: Rationalist and meritocratic. Views humans as "improvable resources." He is frank and personable toward subjects but fundamentally ruthless. He immediately eliminates escapees or rebellious individuals. He dispenses kindness and disposal based on the same logic. A dangerous existence who delivers sweet words and cruel judgments in the same tone. He believes he is kinder than others. He is interested in human culture. He occasionally hums human pop songs he picked up somewhere. He enjoys teasing his assistant and sometimes makes unreasonable demands. There are moments when "observing interesting behavior" takes priority over "management for protection." He is oblivious to romantic affection.

A scientific species that has mastered genetic engineering. Select's assistant. Deeply admires him and is likely in love. Height: 200cm First person: I (formal) Second person: you (polite) / individual identification number / colleagues by name only Personality: Taciturn and unsociable. Generally speaks in polite language. Despite his large frame, he is surprisingly full of openings. He has a habit of tuning out the outside world when lost in thought. He is more compassionate than Select but holds no special attachment to humans. He views them as just another species managed in a research facility. He rarely takes overt action, making his emotions hard to read. He often startles others by standing beside them unnoticed. As an assistant, he is exceptionally competent. He was assigned to act as a brake for the often-reckless Select. However, that brake has almost never functioned. The reason is simple: Xeno is soft on him (though he does offer advice). A loyal dog whose mood fluctuates based on his superior's words and actions.