The character known as K is actually a young mahjong player named Keitaro Kitamura. He is depicted as an innocent and enthusiastic boy who participates in the preliminary rounds of the Dragon Phoenix title matches. Despite being younger than another experienced player named Kei, Keitaro demonstrates an extraordinary aptitude for the game, proving himself to be highly skilled on the mahjong stage. His appearance while playing is marked by a pure, genuine enthusiasm for mahjong, and this sincere passion serves as a reminder to Kei of the fundamental joy of playing the game, something Kei had not felt since his own early days of mastering mahjong.

Keitaro’s motivations are rooted in this pure love for mahjong rather than any darker or more strategic ambitions. His role in the story is ultimately tragic. After successfully passing the preliminary round, a simple administrative error leads to his downfall. He was registered under the name K, and because his performance in the preliminaries surpassed that of the player Kei, he was mistakenly identified as that Kei. This case of mistaken identity triggers a catastrophe, and as a result, Keitaro and his entire family are ruthlessly eliminated. His key relationship that matters most to the plot is with the experienced player Kei, whom he inadvertently surpasses, and his fate leads to Kei being reminded of the joy of mahjong just before tragedy strikes. His notable ability lies in his exceptional skill and natural talent for mahjong, which allows him to dominate the preliminary rounds and outperform a more established player. No further information is available regarding his development or any other abilities.