Tōko Kirigaya is a second-year student at Tsukinomori Girls' Academy and plays guitar in the band Morfonica, where she also designs the group's costumes. Her family runs a traditional kimono shop, giving her deep knowledge of fashion and garment construction; she uses this expertise to manage her own fashion brand, "TOKO," specializing in T-shirts. She lives with her parents and strict grandmother, who forbids guitar practice at home and insists Tōko participate in traditional activities like tea ceremonies. She had known Tsukushi for a long time but only became properly acquainted after joining CiRCLE, having previously mistaken her for "Tanaka-san" or "Yamada."

Tōko stands 164 cm tall (approximately 5'4 ½") with long, wavy blonde hair and light-brown angular eyes. Her typical casual outfit consists of a light-blue jacket over a salmon hoodie, a black shirt printed with repeating vertical "BLACK" text, dark blue shorts, and multicolored sneakers, accessorized with a gold-pendant necklace and a thin braided belt.

Exuberant and approachable, Tōko enjoys popularity at school and online as the influencer "TOKO." She frequently uses gyaru slang like "yabai," "maji," and "mikuron" and habitually takes spontaneous selfies, even during band performances. This spontaneity sometimes causes friction, like when she playfully teases Tsukushi or clashes with Rui due to their differing personalities. During the "An Étude to Spread Our Wings" event, Rui criticized her guitar playing and denied her a prominent solo. This motivated Tōko to seek rigorous training from skilled guitarists Sayo, Kaoru, and Tae to improve.

Academically, Tōko struggles, requiring supplementary classes and often neglecting homework, which increases her workload. She wakes daily at 5:00 AM and shares the same height as peers Tae and Nyamu. Her visual design has been adapted for crossovers, resembling Shion from "That Time I Got Reincarnated as a Slime" and Power from "Chainsaw Man."