Kai devil

Kai, one of the main protagonists, appears in the end of the very first episode of the show; at the time Kai is the team captain of the Blade Sharks, as well as the 爆転シュート ベイブレード world champion. Tyson Granger, another protagonist of 爆転シュート ベイブレード and Kai meet after one of Kai's 'underlings', Carlos, loses to him. Kai defeats Tyson as easily as Tyson did Carlos, though he does not use his bit beast for this victory. Later on, Kai kidnaps Tyson's genius friend Kenny, and is challenged によって Tyson for his freedom. The fierce battle ends in a tie thanks to Tyson's new bit-beast, Dragoon. Kai releases Kenny...

kai was feeding his cat when it happened. a strange blader wearing veils was approaching him. "i want to battle you," she said. "i've quit blading," kai replied. "i see," the newcomer said, "so あなた don't accept my challenge. ok then i'll have to find someone else. i think tyson will be interested."
kai looked up as soon as he heard tyson's name. "how do あなた know him?" he asked. "he's my friend. he brags a lot about you," the girl replied. "i accept your challenge." the girl laughed. "when do we have the battle?" "tomorrow morning at ten." so the girl nodded and went away.
since six years after...