Kunio (くにお) is one of the two main protagonist of Nekketsu Kouha Kunio-kun.
- Hair Color: Brown
- Eye Color: Brown
- Height: 175 cm (5'7")
- Weight: 65 kg (143 lbs)
- Blood Type: AB
- Status: Alive
- Affiliation: Nekketsu High School (Southside High School in Crash 'n the Boys: Street Challenge)
- Year: Sophomore (Nekketsu Kouha Kunio-kun series), Senior (Downtown Nekketsu series)
- Alternate Names: Mr. K (Renegade), Sam Powers (Super Dodge Ball), Alex (River City Ransom), Jeff "Crash" Cooney (Crash 'n the Boys: Street Challenge)
- Hobbies: Dodgeball, Football, Hockey
He serves as the famous guardian of Nekketsu High School against rival schools and is the captain of the school's Dodge Ball team. A righteous delinquent with a strong personality, he has a heart of gold and cannot abandon those who are in trouble. He has a weakness for pretty girls, which often leads to heartbreak.
Although he is the captain of the Dodge Ball club, he excels at other sports and participates in many of the other sports clubs at his school as an assistant, where he displays ace-class skills that exceed the capabilities of regular club members.
Kunio's best friend and rival is Riki Samejima, the banchou of Hanazono High School. After joining forces in Downtown Nekketsu Monogatari, the two are always seen working together as allies against a common threat, but they continue their rivalry in multiple sports competitions.
Kunio first appears in Nekketsu Kouha Kunio-kun, where he avenges his beaten friend Hiroshi, an honor student and a sophomore (2nd year student) like him. He defeats Hanazono High School students and their banchou Riki Samejima, at Shinjuku Station, then he faces off against "Yokohama Funky" bousouzoku gang and their leader, Shinji the Blue Emperor. Afterwards, he fights a girl gang from the Taiyou Academy and their sukeban, Misuzu. Finally, he faces Sabu, the leader of the Sanwakai crime organization.
In the Famicom version of the game, instead of avenging Hiroshi, Kunio has to rescue him from Sabu.
In the arcade version of Renegade, Kunio is changed to a nameless vigilante who fights against street gangs in order to rescue his girlfriend. In the NES version, Kunio is replaced by the same nameless vigilante, now named Mr. K. Mr. K just happens to run into the wrong part of town and gets in trouble, but he won't run away from it.
- In Renegade, Kunio was changed to a nameless vigilante who had to rescue his girlfriend from a gang of thugs. The NES version of the game gives him the name Mr. K.
- In the NES version of Super Dodge Ball, Kunio was named Sam, a captain of Team USA.
- In River City Ransom, Kunio is known as Alex. His full name is expanded to Alex Kun in River City Ransom Underground.
- In Crash 'n the Boys: Street Challenge, Kunio was named Jeff "Crash" Cooney, a captain of Team Southside High School.
- He is named after Technos Japan's former president, Kunio Taki.
- Kunio has no surname. The closest he has had to a surname is Oyama, due to second Oyama brother in Double Dragon 3: The Rosetta Stone being named Kunio. In the TV drama, he is given the surname Fu'unji (風雲児).
- Kunio's classic white uniform from the 1980s to the early 1990s bares a resemblance to Shūtarō Mendō from the manga and anime Urusei Yatsura.
- Kunio is the only character whose name was not mixed up in Nintendo World Cup.
- Kunio's birthday is on November 27, the same as Bruce Lee. Kishimoto choose this date in order to pay homage to Lee.
- Kunio can be considered Nekketsu High's Banchou (番長), a Japanese term used to call the leader of a juvenile delinquent gang. This can be noticed due to the fact most of his schoolmates often look up to him (examples include Hiroshi and Sugata), and is always the captain of the Nekketsu High sports team in every respective game. Also, the typical image of a banchou is an uncouth fighter who has a strong sense of honor.
- The character Yusuke Urameshi from the anime and manga series Yu Yu Hakusho bears a resemblance to him.