Kotaro Takebayashi is a quiet and analytical student within the fantasy parody setting. He has black hair combed over the sides of his head, wears round eyeglasses, and dons the standard Class E uniform. His personality centers on statistical analysis and observational skills, favoring data-driven approaches over emotional or practical knowledge. This analytical tendency manifests in situations ranging from calculating physics during combat exercises to assessing risks.

His demolition expertise shines; he easily memorizes explosive techniques and effectively applies shaped charges or flash bangs during missions to distract adversaries or facilitate escapes. Academically, he excels in science and maintains strong overall scores, though he displays clumsiness during physical activities. His interests heavily emphasize anime culture and maid cafés, leading him to enthusiastically evangelize these hobbies to peers like Ryoma Terasaka, with whom he frequents such establishments. This otaku-focused behavior frequently provides lighthearted moments.

He collaborates scientifically with Manami Okuda, such as tending to sick classmates or conducting research. He avoids prolonged discussions about explicit real-world relationships, as seen with Taiga Okajima. His reserved nature makes him more comfortable speaking with individuals like Ryuunosuke Chiba, where direct eye contact is less necessary.

He maintains a consistent role as a supporting strategist and explosives specialist within the class's dynamic.