Takashi Yamada, a middle school student with spiky blue hair and sharp black eyes, wears a bold white-and-blue striped t-shirt, vibrant fuchsia shorts, and electric-blue sneakers. Outgoing yet mischievous, he relentlessly pursues opportunities to provoke classmate Naoko Watanabe into transforming into the fire-breathing dinosaur Gauko, driven by insatiable curiosity and a disregard for personal risk. His schemes often spiral into chaos, resulting in comedic physical mishaps, yet he shifts to focused responsibility during crises, such as efficiently aiding others in the "Candy Strategy" incident. Though obsessive in his quest to trigger Gauko’s appearances—sometimes sulking when unsuccessful—he reveals flashes of loyalty and collaborative skill when teamwork becomes essential. His dynamic with Naoko balances playful antagonism and unexpected reliability, always anchored by his singular goal: witnessing the fiery spectacle of her metamorphosis.