Agiri Goshiki functions as the narrative's tritagonist. A ninja from Sonya's organization, she attends high school primarily for assignments. Her appearance features long dark purple hair with swept-aside messy bangs and long thin strands, complemented by purple eyes. She wears the standard school uniform, distinguished by blackish-grey ankle socks.

Agiri consistently exhibits a calm, friendly, and laid-back demeanor. She resides without authorization in a disused ninja club room on campus. Her interactions frequently involve demonstrating unconventional gadgets or techniques labeled as specialized "ninjutsu," executed without explanation. These actions routinely perplex Yasuna, who often accepts Agiri's logic, and Sonya, who typically distrusts her. Agiri maintains a serene composure and unchanging sleepy vocal tone in all situations, whether confronting threats like an escaped bear or performing mundane tasks.

Her background traces to a lineage associated with ninja traditions, evidenced by her access to numerous ninja-themed objects and techniques. Her parents work as farmers, while some relatives operate a privately owned theme park. She utilizes various concealed mechanisms within her residence and is occasionally seen selling ninja-related gadgets to others, such as Yasuna. In one documented incident, she intervened during an assassination attempt on Sonya, neutralizing the threat with a standard boomerang. No significant character evolution or additional narrative development across extended media is documented.