Hanako Mikado, Gao Mikado's younger sister and a third-grade student at Aibo Academy, demonstrates unwavering support for her brother. She attends his buddyfights, enthusiastically cheering him on when others express doubt. Hanako openly admires Gao's persona as the Mighty Sun Fighter and is also a fan of Tasuku Ryuenji. Her upbeat, energetic personality drives her deep familial affection. She actively seeks time with Gao and his friends, including his buddies Drum, Bal, Batzz, and Chibi Panda. As a beginner buddyfighter, she learns the game alongside Gao and later practices with Bal Dragon. During the WBC Cup World Championships in Triple D, she encourages Gao, Tasuku, and even Gaito. A notable bond forms when she meets the newly hatched Bal Dragon in Triple D episode 2. They practice buddyfighting together, signaling Hanako's aspiration to participate in matches. She reappears in Triple D episode 14, playing buddyfight with Bal before Gao's match against Dai Kaido. Her connection to Gao's themes manifests in the "Buddyfight Triple T 'Hanako Mikado'" spell card, named after her. Its flavor text—"My brother, thank you as always!"—complements an effect that adds cards to the gauge, enhanced by a Sun Dragon's presence on the field. She observes Gao's resemblance to the Mighty Sun Fighter during his Future Force activation, noting the similarity alongside Genma Todoroki. In Future Card Buddyfight X episode 15, she becomes involved when Gao turns into a ghost from overusing an Impact Card, leading to a confrontation with a Legend World entity also named Hanako. Throughout her appearances, she remains a supportive family member and enthusiastic beginner buddyfighter.