Kunio Yamagata teaches alongside Miss Machiko at Arama Academy. He persistently pursues her romantically, harboring deep feelings yet battling nerves when expressing them. His ongoing efforts to ask her on a date are characterized by timidity and hesitation. This romantic pursuit forms a recurring subplot, placing him among several male characters—students and faculty—vying for Machiko's affection. The narrative sometimes touches upon his family life, including an episode where his elderly mother bonds with Machiko in a bathtub, unintentionally creating discomfort for Machiko despite the intended familial connection. Across the franchise's anime, manga, and live-action adaptations, his character remains unchanged. His role consistently provides romantic tension through unassertive advances toward the protagonist. The documented media does not explore his backstory, motivations, or substantive changes in his interactions or personality over time.