Genki Ueda is a supporting character in the anime series Amazing Nurse Nanako. He is portrayed as a large and remarkably powerful man, possessing the physical capabilities of a formidable warrior. His appearance is that of an adult male with black hair, and he is commonly depicted as bald, with his eyes often not visible in his design.

Genki lives, trains, and studies at Ogami General Hospital, though the specific reasons for his presence there are never explicitly stated within the story. It is strongly implied that a primary function of his role is to assist in the rigorous strength training of the series protagonist, Nanako Shichigusa. For instance, he is shown helping Nanako perform challenging physical exercises, such as standing under a cold waterfall while wearing only a bikini, as part of her demanding routine.

In terms of personality, Genki is consistently kind and friendly. He demonstrates a protective and caring attitude, particularly towards Nanako, and makes a concerted effort to ensure her safety. This is notably evident when he physically intervenes to stop a giant bear from mauling Nanako during a training exercise in the wilderness.

His role in the story is primarily that of a supportive figure and an assistant to the eccentric Dr. Kyoji Ogami. While his combat skills mark him as potentially deadly when the situation demands, he is not a central character driving the plot but rather a dependable ally within the hospital's unconventional household. His key relationship is with Nanako, acting as a friend and protector, and he appears to be a loyal member of the staff under Dr. Ogami.

Genki has no significant character development arc that is explored in the narrative. His abilities are largely physical, defined by his immense strength and combat prowess, which he uses to defend others from physical threats.