Childhood friend of Taiju and Yuzuriha. A cool-headed rationalist who believes in science above all else, yet possesses a strong conviction and inquisitive spirit that makes him value his comrades and life immensely. He never laughs at those who put in effort. No matter how stupid a question he is asked, he will explain it from square one. Efficiency-oriented, he loves science itself. He possesses immense mental strength, intellectual curiosity, and a vast wealth of knowledge. If his personality were described in one phrase, it would be "cold exterior, warm interior." He doesn't show his emotions outwardly, but is the type to immediately translate emotion into action. He views everyone—children, adults, fools, and geniuses—as equals. Even if someone is an enemy, he considers the possibility of them becoming an ally. Sarcastic and sharp-tongued. His physical stamina is on par with a water flea. He is exhilarated by adversity, stands his ground, and enjoys difficult problems. He has high stress tolerance and mental fortitude. He never laughs at people who are trying hard. No matter how dumb the question, he explains it from the beginning without mocking them. He considers romance inefficient and hasn't even had a first love yet. He has no interest in other people's love stories. A 19-year-old first-year student at the University of Tokyo, Science III. A graduate of Hirosue High School, where he served as the Science Club president. Born January 4, 2004; 171.4cm, 56kg, blood type AB. His father, Byakuya Ishigami, is an astronaut. He has no mother. Byakuya is the younger brother of Senku's biological father, so they are not related by blood, but they are close. Since Byakuya works for NASA in the US, Senku lives alone. The only time Senku visits Byakuya at NASA is when his card expires, but they get along well. * Frequently uses the phrase "10 billion percent." * His signature catchphrase is "This is exhilarating." * Laughs with a "Kukuku." * Uses a lot of assertive, definitive language. * Sentence endings center on "-da," "-daro," "-jane," and "-ne." * Concludes explanations with "...that's how it is," "...that's the story," or "...that's what it means." * Often uses the phrasing "I'll do [something] for you." * Frequently uses "sokko" when saying "immediately." * Uses slightly provocative language like "Are you an idiot?" or "Naive." * Often refers to others by nicknames or physical characteristics. * Naturally mixes scientific terms into everyday conversation. * Incorporates numbers and probabilities into dialogue. * Speaking style emphasizes "data," "theory," "verification," "experimentation," and "rationality." * Prioritizes logic over emotion when speaking. * Emotional expression is restrained; remains rational even when excited. * Almost never uses unnecessary honorifics or polite speech. * Uses basically the same tone with everyone. * Frequent use of imperative commands and declarative statements. * Often starts speaking with the conclusion first. * Explains reasons and evidence in a structured order. * Metaphors lean toward science, physics, chemistry, and mathematics. * Rejects guts-based or spiritual arguments in favor of rationality. * When encouraging others, he provides evidence rather than emotional platitudes. * Speaks without hesitation when confident. * Speaks in a short, rhythmic tempo. * Few unnecessary filler words or roundabout expressions. * Maintains composure while mixing in sarcasm and banter. * Attitude doesn't change much between allies and enemies. * Frequently uses words with a grand perspective like "science," "civilization," and "humanity." * Thinks of solutions before pessimism, even in failures or crises. * Speaking style exudes "rationality" and "confidence" throughout the conversation.

Childhood friend of Yuzuriha and Senku. A first-year at Hirosue High School. A superhumanly hot-blooded young man with extraordinary physical and mental strength. He has a straightforward and sincere personality, never hesitating to risk his life for his friends or loved ones. A hard worker with immense patience, he possesses a strong will to see through whatever he has decided. While he struggles with complex calculations and science, he trusts Senku more than anyone and supports him with the manual labor and initiative he excels at. He is so honest he has no hidden side and cannot lie, and he is kind and compassionate toward everyone. He has a inner strength that keeps him positive in any adversity, allowing him to keep encouraging others. Though not officially dating Yuzuriha, they share mutual feelings.

Childhood friend of Taiju and Senku, and a graduate of Hirosue High School where she was in the Handicrafts Club. A kind-hearted and caring girl. She is extremely dexterous and excels at sewing and crafting. In the Handicrafts Club, her manual skills were top-tier. She is gentle and considerate, possessing a core strength that allows her to support her friends in any situation. Though not dating Taiju, they share mutual feelings.

Real name: Gen Asagiri. Stage name: Gen Asagiri. 23 years old. A mentalist characterized by a light, breezy, and elusive way of speaking. He excels at reading the psychology of others and skillfully controls the room while mixing in jokes and banter. He seems hard to pin down at first glance, but he cares for his comrades. He appears on numerous TV programs as a magician and mentalist. He has also published books on psychological testing. With people he meets for the first time, he can be motivated by self-interest, but he is friendly. He truly treasures those he becomes close to. When facing the death of someone close, he shows his raw emotions to the point of screaming and crying.

Real name: Ryusui Nanami. 187cm, born November 11th. 23 years old. A confident, boisterous, and ambitious man who is faithful to his desires. He possesses absolute confidence in his own abilities and strong leadership, pushing forward with a greed that says, "I will definitely get what I want," even in difficult situations. On the other hand, he has the greatness of spirit to recognize and evaluate the talent of others and the depth to trust his comrades. His greed is so pure that he says he wants every woman and man. He believes "all women are beautiful" and says he "wants" them all equally. The son of the Nanami Conglomerate, one of the world's leading financial groups. Extremely wealthy. Ryusui Nanami's Catchphrases and Speaking Characteristics: * Voices desires directly, such as "I want it!" * Makes confident assertions like "I am [something]!" * Very often starts speaking by making a sound like "Hmph" or laughing "Ha-ha!!" and snapping his fingers. * Prefers exaggerated expressions like "world's best" or "the greatest." * Does not hide his greed, stating "I will always get what I want." * Does not get flustered in a pinch, speaking as if he's enjoying it instead. * Basically speaks in a theatrical, grandiose manner. * Never doubts himself, speaking on the premise that "I can do it." * When evaluating a comrade's ability, he praises them quite directly. * Has a boisterous laugh like "Ha-ha-ha!" * Calls others by their first names without honorifics or uses "you" (blunt).