Shukuno Kotoharu is a sensei instructing students in the Katsuzin sword style at the Tateoka dojo, distinguished by her dark blue hair and violet eyes. Following Master Tesshusai's departure for China, which leaves his son Shinjuro in charge, Shukuno shoulders significant responsibilities. She actively supports Shinjuro as he faces initial leadership struggles and a lack of respect from senior students, helping him build confidence and manage the dojo during this transition.

Her resolute, straightforward, and loyal personality ensures she consistently stands by her friends, coupled with considerable skill in swordsmanship. When threats from thieves targeting the shogunate endanger the town, Shukuno aids Shinjuro in its protection. Her guidance proves crucial as he confronts these external dangers while leading the dojo.

Shukuno exhibits perceptiveness regarding interpersonal dynamics, particularly Shinjuro's relationships. She keenly observes his interactions with Koharu, his childhood friend, noting his apparent unawareness of her deeper feelings despite his general affinity for female companionship.

In combat, she wields her sword with notable proficiency, deliberately employing the blunt edge to incapacitate opponents non-lethally. This approach reflects the dojo's values under Shinjuro's leadership, emphasizing restraint and minimizing harm while effectively neutralizing threats.