Kai is one of the main characters of Jibaku-Kun (as known Bucky: The Incredible Kid or Bucky: Searching for World 0) series, a creation of Ami Shibata.
Kai is a strong and determined boy. It is loyal to friends, and does everything for them. Kai is one of the strongest disciples of Master Funen, and the Great Child of Trios, the Third World. Kai meets Pinky and Bucky when they are going through Trios, and decides to accompany them on the journey to Spaak and the World Zero. Since childhood he is grateful to Spaak, who saved his village Monster Troublemaker Taurus Giant (the same village Spaak saved again with the help of Bucky). Since then much Kai trains under the tutelage of Master Funen, which was also the victim of a curse cast by the "Needle Tower". The reason to follow up with Bucky in Zero World is training to become stronger, and find Spaak in order to thank him.
In the final episode, he was shocked to see Master Funen in his human form during the final battle against Slash.
Kai appears as a tall elf man with long spiky hair which is horizontal in appearance and has green linings on his elfin ears.
His primary outfit is a magenta high-neck sleeveless shirt with white linings and the center of his shirt, black Chinese pants with sky blue scarf on his waist, white socks and black Chinese toe shoes. He also wears a blue green wristbands in both of his wrists and wields the red staff.
During Episode 18 while aiding Runmaru in one episode, He was seen wearing a light blue traditional Japanese jacket with bandages in his chest and stomach, white sarashi shorts and black Japanese sandals.
He is later seen wearing a aqua blue traditional Japanese kimono dress, white tabi and a black Japanese geta. He also has a geisha make up on his face while posing as a geisha.
- Dragon Strike: A blow that causes an explosion of fire coming out of the eyes of his spirit Bakzan, This technique was taught by Master Funen, and all the Children of Great Trios know this technique.
- Supremacy: A technique that requires time and dedication to be learned. Is to find the vital point of the enemy.
- In the Japanese version, he is voiced by Hiroshi Kamiya is best known for voicing Takashi Natsume. In the Filipino Dub, he is voiced by Jefferson Utanes is best known for voicing Son Goku in the Dragon Ball franchise. He also voices both Dartagnan and Ali Babah in her young gay form in the same series.
- He is the only character does not join with Bucky and Pinky when they are sided with Ash and his rebellion group in Episode 21 and he is known to be taken hostage by Joan.