|Family||Karasumaru Daiki (brother)|
|Occupation||Juuzenji High student|
Karasumaru Kosuke is the younger brother of Daiki and the captain of the Ten Knights though he is often mistaken for a grade-schooler due to his appearance. While not a very skilled fighter, his limited "reading" ability allows him to anticipate his opponent's next move based on their facial expressions. In spite of his status, the Ten Knight's captain is noted for being a coward with little interest in combat and frequently calls his older brother for back-up. Kosuke spends most of his time on the Juuzenji High rooftop eating ramen. Later he was defeated by Miu who covered her face using a clothe. He appeared again at his brother's hideout asking for help only to be beaten by his brothers subordinates.