TV-Series
Description
Kaoru Kaido, nicknamed "Viper" or "Mamushi," attends Seishun Academy as a second-year in class 2-7. Born May 11 under Taurus, he stands 173-174 cm tall with blood type B. His family consists of mother Kaidoh Hozumi (40), father Kaidoh Shibuki (37), a bank employee, and younger brother Kaidoh Hazue (11).

Kaido projects a serious, unsociable demeanor often misinterpreted as intimidating, yet reveals compassion through interactions with small animals like Ryoma Echizen’s cat Karupin and a documented fear of the supernatural. He once impersonated Ryoma to avoid disappointing adoring children, winning their admiration despite embarrassment. His strong sense of justice drives actions like shielding Ryoma from a stray ball or carrying an injured Momoshiro Takeshi. Discipline defines his routine: 5:00 AM roadwork, 25 km daily marathons, weight training, and meticulous habits like ironing clothes and room cleaning. He collects bandanas, runs marathons as hobbies, and spends allowances on training gear.

In tennis, Kaido is a counter-puncher famed for extraordinary stamina built through self-imposed triple-standard training. His signature Snake Shot—a curving forehand evolved from the Buggy Whip Shot—exhausts opponents by forcing wide coverage. Variations include the Boomerang Snake (accidentally developed against Fudoumine’s Kamio Akira, curving out-of-bounds around the net pole); Short Snake (sharper, shorter curve); Reverse Snake (for confusion); and Tornado Snake (a spin-driven straight shot reducing air resistance). He adapted Hiroshi Yagyuu’s "Laser Beam" into the "Gyro Laser" by fusing it with Tornado Snake’s spin. Though his style evolved to include aggression, his core strategy remains draining opponents through extended rallies.

Kaido’s journey features a fierce rivalry with Momoshiro Takeshi, marked by competition yet mutual respect. He initially trained under Inui Sadaharu, whose data methods refined techniques like the Boomerang Snake, leading to doubles partnerships. After the national tournament, he succeeded Kunimitsu Tezuka as Seigaku’s captain. He later joined Japan’s team for the U-17 World Cup.

His preferences include favorite subjects English (contrasting struggles with Mathematics and Science), foods yam soba (zaru), yogurt, and 100% fruit juice, color blue, and zoo visits to observe polar bears. His mottos are "In for a penny, in for a pound" and "Slow but steady wins the race."