Sacchū, a mouse-class fairy allied with the Magical Five and their magical girl partners, delivers critical tactical support. He achieves this through direct sensory linking with the girls and providing real-time enemy analysis systems. His combat skills encompass firearms proficiency, including pistols and grenades, alongside close-quarters weaponry like spiked brass knuckles. He actively participates across multiple operational arcs: the Distonian War, Babel Brigade conflict, Okinawa deployment, Ukraine mission, Saving Phoenix operation, and New York engagement.

Sacchū consistently ends every sentence with "chuu" and favors snake as his preferred food. Visually and in naming convention, his design shares distinct similarities with Pikachu. He maintains operational relationships with core Magical Five members Asuka Ootorii, Kurumi Mugen, Tamara Volkova, Mia Cyrus, and Lau Peipei, plus secondary ally Chisato Yonamine. He belongs to a broader fairy group including Tabira, Ackler, and Kilgee.

Beyond combat, Sacchū's role includes intelligence gathering and coordinating magical systems during missions, exemplified by his analysis of enemy magic during the Russian mafia's interdimensional bridge incident.