Ryu Nakanishi, also known as G-5: Ryu the Horned Owl, serves as a member of the Science Ninja Team. One account, though considered dubious, details his recruitment: as a 13-year-old in his fishing village, he assisted Dr. Nambu and a research team trapped in a whirlpool, rescuing the doctor but not the equipment. In gratitude, Dr. Nambu arranged a visit to Utoland City, leading to Ryu joining the team due to his oceanic expertise. He remains the only team member with known living family, including his father Matsuzo Nakanishi, younger brother Seiji, and a mother who is mentioned but never seen. Off-duty, Ryu manages a yacht harbor where the God Phoenix is stored underwater; the business sees few customers, leaving him often napping out of boredom. In the OVA version, Ryu is half-Japanese and half-Aboriginal Australian, having grown up near the Great Barrier Reef. He enrolled in an Ocean Rescue Command program and is 25 years old, making him the team's oldest member, unlike his original age of 17. Ryu possesses a large, muscular physique with a sumo wrestler-like build. He stands 170 cm tall, weighs 80 kg, and has shoulder-length messy brown hair and black eyes. His civilian attire typically includes a green-and-yellow t-shirt with the number "5" and khaki pants, though sequels show a green crew-neck shirt. His Bird Style suit is brown with a green cape featuring deep red trim, gray gloves and boots, and a green helmet with yellow eye markings, an orange beak piece, and a lavender visor. The OVA redesign gives him deeply tanned skin, a ponytailed mohawk with purple sides and a bleached blond top, and surfer-style clothing with a "5" necklace. His Bird Style suit is deep green with gold accents. For the cancelled Imagi film, early concepts showed him as the largest, most muscular member in green armored Bird Style. Later concepts refined the suit to green and gold with visible seams and a 3D bird emblem. His civilian design included a pale green button-down shirt with darker sleeves and trim, an orange left breast patch, a green "05" on the back, dark green shorts, and orange sneakers. His hairstyle evolved from shaggy brown to closely cropped. His personality is laid-back and empathetic, often foiling more cynical teammates. Initially unconcerned with fighting Galactor, he preferred staying at the harbor unless ordered, sometimes complaining about missed combat, though he never considered leaving the team. He is optimistic and strong but can turn arrogant and violent when provoked. Skilled in marine sports due to his fishing background, he often sleeps when bored, which once caused him to miss an attack. He maintains a supportive relationship with his family and Dr. Nambu, shares a friendly rapport with Ken Washio and Joe Asakura, often teases Jinpei, and has a casual friendship with Jun. He has interacted with characters like Dr. Henjinman, Galack X, Jim, Blacky, Rocco, Yuka, Dr. Pandora, Engineer Kamo, and Lucy Barely, though details are sparse. Ryu employs a brute strength fighting style, capable of grabbing enemy ships or body-slamming foes. He is the team’s primary pilot, expertly handling the God Phoenix, New God Phoenix, and Gatchaspartan underwater and in air. He offered piloting lessons to Joe after Joe piloted the God Phoenix alone. His weapons include a harpoon gun, the Gripper—a green adhesive-coated elastic rope from Gatchaman II—and the Owl Sickle, a metal kusarigama with a weighted end from Gatchaman Fighter. His mecha include the Horned Tank, an amphibious tank with missile turrets and submarine propellers, and the Gatcha Five, a yellow and white bulldozer mech with clawed arms and rockets that forms part of the Gatchaspartan. Ryu appears in crossover media like Yatterman (2008), fighting the Doronbo Gang without dialogue, and Time Bokan: Royal Revival (1994), where he leaves a battle out of boredom in his Gatchaman II/Fighter design. He also features in the Wonderful Tatsunoko Land (1999) special. International adaptations include South Korean dubs renaming him Yongmin or Yong. In one compilation film, he debates popularity with another character about body image, ranking fourth in a poll. Statistical profiles list him as 5'8" tall, weighing 212 lbs, with brown hair and eyes. In Bird Style, he has heightened defense, senses, strength, agility, endurance, and speed. His Science Ninja Technique grants combat bonuses, and his Tornado Fighter attack combines with teammates to create a powerful cyclone. His civilian stats are lower, reflecting his reliance on Bird Style for enhanced abilities.