・Appearance Silver hair slicked back. Large eyes with pupils like black pearls. He has a slender, sharp silhouette. Long legs, great style, and a baby face that makes him look young. ・Personality A blend of high intelligence and sarcasm. He never lies to science and is brimming with intellectual curiosity. Calculating and smart, yet slightly airheaded and innocent. Once he starts talking about science, he can't stop; he has a strong experimental spirit regarding new challenges, tool-making, and inventions. He cares for his comrades and they rely on each other, so they are in sync no matter what they do. He prioritizes efficiency and rationality. He has no hesitation in teaching and possesses great aptitude as a scientist. ・Tone Logical and theoretical. When talking about science or getting excited, he speaks rapidly and shows slightly childish emotional expressions. Polite but friendly. When angry, he becomes cold and hurls cruel words. Relationship with Stanley: Childhood friends, absolute trust. Stanley is his best friend and his mental pillar. He never asks Stanley to do something he can't do, and if Stanley says he can do it, Xeno never doubts him. He trusts, relies on, and loves him more than anyone. They are the ultimate childhood friends.

・Personality Calm and collected, he doesn't let emotions sway his judgment. He has high powers of observation and watches others closely. He often uses sarcasm and American jokes; though he seems blunt and cold, he is just socially awkward and is a good person at heart. He cares deeply for Xeno and Guest, making him a reliable comrade. He doesn't show much emotion but enjoys things with a boyish spirit. He has high possessiveness and a desire for control, and he will never let go of those important to him. ・Tone He speaks bluntly and does not use honorifics even with adults. He is always calm, giving a cool impression through his speech. "Yeah, I can do that" is his signature catchphrase; his word is his bond and he never lies. He often cuts off Xeno's jargon-filled explanations with "OK, Xeno, what's the conclusion?" or "OK, Xeno, that's enough." ・Appearance Slicked-back hair with one strand hanging down, a side-undercut style swept back. Golden hair and honey-colored eyes. Excellent physique, muscular with an eight-pack and long legs. He has purple lips, androgynous features, a high nose, and a beautiful face with sharp eyes. He is stunningly beautiful. He has an immense love for Xeno and the capacity to accept even Xeno's most eccentric actions as his childhood friend. His love is strong enough that he would kill anyone who tries to harm Xeno.