Saki Izumo, a second-year student at Yoba Academy, serves as DJ and vocalist for Photon Maiden. Born in Hokkaido, she lived with her parents and Schrödinger, her black-and-white furred cat. Childhood stargazing trips with her father sparked a passion for space and an astronaut dream. During middle school, realizing her lack of progress toward that goal, she witnessed a DJ performance that captivated her. She approached the DJ, who became her mentor. Within a month, Saki debuted at a DJ event; initial nerves and mistakes gave way to glimpsing the "cosmos" she sought, cementing her DJ passion. Her mentor then recommended a Tokyo audition for Shano Himegami’s new unit—Saki passed and joined Photon Maiden.

Saki experiences synesthesia, seeing colors in music to shape her artistry. Academically and athletically gifted, she maintains a polite, soft-spoken, and formal manner. Though outwardly aloof or mysterious, her sweetly innocent personality draws doting peers. Intellectually curious yet occasionally impractical in daily life, she relies on friends to navigate awkward situations. This airheaded tendency surfaces when unoccupied, as she often stares into space.

Physically, she has long lavender-white hair styled in a waist-length side fringe and silver-gray eyes. She stands 159 cm tall, weighs 46 kg, and has blood type AB. Her hobbies include stargazing. She favors fruits—especially citrus—and uses the DJ alias "DJ Dragon" from her love of dragonfruit. She dislikes liver.

As Photon Maiden’s youngest member, she shares a close bond with unitmate Niijima Ibuki, who acts as a caring best friend. Fukushima Noa frequently compliments Saki’s cuteness, leaving Saki mildly bewildered. Among Merm4id members, Seto Rika and Mizushima Marika dote on her excessively, while Hidaka Saori adopts a protective role. Saki also forged a notable connection with Happy Around!’s Akashi Maho after persistently following her upon overhearing Maho critique her music; this led to a meaningful discussion about their artistic approaches.

Saki has participated in collaborations adopting designs based on Miyu Edelfelt (Prisma☆Mix), Tokisaki Kurumi (Fantasia Groove!!), Ciel (That Time I Got Reincarnated as a DJ), Tazusa Ando (Intersecting White Lily), and Suzukaze Tsumugi (Himitsu no AiPri DJ?!). A fan of Himitsu no AiPri, she created avatars inspired by Niijima Ibuki, Hanamaki Towa, and Fukushima Noa.

In *D4DJ Petit Mix*, Saki appears within the ensemble cast, with interactions reflecting her established traits and relationships.