Koto serves as the referee in the Dark Tournament. Like Kurama, she is a fox demon but doesn't seem to possess any special abilities. Later, she is replaced by Juri and transitions to commentary. Koto also officiated in the Makai Tournament. She enjoys idol status in both the human and demon realms and appears to have a crush on Kurama's demon form, Yoko.
Often, Koto seemed excessively entertained by the suffering of the fighters in the Dark Tournament, which made her appear somewhat cruel. However, she later reveals that she can only enjoy brutality when both contestants are capable of fighting back. During the tournament, she initiates a ten-count to stop Bakken from assaulting Kurama, demonstrating that she isn't entirely sadistic. She has memorized the entire tournament rulebook.
Briefly, Koto becomes the object of Chu's affection, though she does not reciprocate his feelings. At times, she puts on a cute act, but she is quite sharp and often makes jabs at Juri for being a former 'cocktail waitress'.
