Eikō serves as a supporting character and a prominent prankster within Class 6-2. He frequently engages in teasing female classmates and collaborates with peers like Tomoya to compile popularity rankings, consistently ranking Cocoa Hamana at the top. A dedicated enthusiast, he collects and idolizes Yuuto Takao's notable statements, known as "golden thoughts."

Eikō and his group operate as self-appointed informants, observing and documenting classmates' interactions—particularly romantic developments involving couples like Hanabi and Yuuto or Yui and Kazuma. Their findings fuel an unofficial school publication. While their methods include stalking peers for material, they deliberately withhold sensitive or harmful information. Their comedic presence intensifies through repeated recitations of memorable quotes from the couples they monitor.

His role consistently delivers lighthearted, observational humor within the school setting across all seasons and adaptations.