Gen Asagiri was a professional mentalist and magician active before the global petrification, appearing on television where he first met Tsukasa Shishio during a psychological magic show. Depetrified by Tsukasa roughly 3,700 years later, he infiltrated Ishigami Village to confirm Senku Ishigami's death. Initially opportunistic and self-serving—considering alignment with Tsukasa for perceived advantages like a harem—Gen defected to the Kingdom of Science after witnessing Senku's scientific innovations, including iron production and electricity generation. Senku fulfilling Gen's request for cola solidified this shift, leading Gen to falsely report Senku's death to Tsukasa. Physically slim and average height, Gen possesses distinct bicolored hair: short and black on the left, longer and white on the right. His hair was entirely black before petrification. A jagged petrification scar originally ran from his left eye down his cheek; this healed after his second depetrification, and he later recreated it with paint. His typical attire features a lavender-pink overcoat layered over a wheat-colored yukata, secured by an orange obi and thin rope, often worn without footwear. Gen's personality blends calculated manipulation with underlying loyalty. He openly identifies as a "world-class smooth talker," leveraging psychology, deception, and strategic forecasting to advance the Kingdom of Science's goals. Though less academically proficient than Senku, he bridges scientific concepts for non-experts and motivates allies through interpersonal tactics. His demeanor shifts between performative nonchalance—feigning incompetence to avoid labor or combat—and intense focus during crises, maintaining composure under threats like interrogation or violence. Despite outward cynicism, he exhibits genuine care for allies, forming a close bond with craftsman Kaseki (who frequently enlists his help) and showing protective instincts toward the child Suika. Quirks include theatrical reactions to scientific revelations and frequent use of Pig Latin. His abilities center on human psychology and persuasion. As a mentalist, he deciphers nonverbal cues and motivations, exemplified by interpreting Kohaku's pictorial message and predicting adversaries' actions, like preparing concealed blood packs to survive Magma's assassination attempt. He excels in vocal mimicry and cross-gender impersonation, though Kohaku noted his height limits female disguises. Additional proficiencies include stage magic, Morse code communication, and fluency in Japanese and English (used during covert negotiations with Ukyo Saionji and interactions with Xeno Houston Wingfield). Lacking physical prowess, he displays unexpected endurance, recovering from severe injuries to traverse long distances for missions. Throughout the Kingdom of Science's conflicts, Gen served as one of the Five Wise Commanders, specializing in psychological strategy. Key contributions include sabotaging Hyoga's spear during the assault on Ishigami Village, facilitating defections from the Tsukasa Empire through impersonations of singer Lillian Weinberg, and manipulating Ryusui Nanami into funding the Perseus ship's voyage despite the Kingdom needing his expertise. His predictive acumen proved vital during the Treasure Island arc, deducing Mozu's self-interest to secure an alliance and navigating tensions within Xeno's American scientific faction, notably bypassing a polygraph test through strategic half-truths. Relationships define his development. With Senku, he evolved from wary collaboration to deep mutual trust, epitomized by constructing a telescope as a birthday gift after learning Senku's pre-petrification pledge to restore civilization. His dynamic with Kohaku transitioned from mutual distrust to tactical rapport, while interactions with Magma remained strained yet pragmatic following the latter's attempted murder. Post-conflict, Tsukasa acknowledged Gen's value despite initially deeming him emblematic of the old world's corruption.