Junko Hokaze is a third-year Tokiwadai Middle School student and secondary leader of Shokuhou Misaki's clique, actively managing its operations due to Shokuhou's hands-off approach. She possesses long lavender hair styled in distinctive ringlet curls, a slender physique, and purple eyes. This hairstyle originated from a salon accident replacing her usual twin braids; she retained it upon learning Shokuhou approved.

Her past traces to the Clone Dolly project's "Ideal" lab, where she was a test subject alongside Shokuhou Misaki, Mitsuari Ayu, the Yumiya sisters, and Senya Yūri. Even as a child, her esper ability held destructive potential comparable to Level 5s but caused severe daily cluster headaches and risked harming others. To protect peers, she isolated herself, warning them away. Shokuhou alleviated her pain using Mental Out, forging Junko's lifelong loyalty. During an Ideal experiment involving Senya's power, a fused AIM entity possessed a researcher, leading to a rampage where Yumiya Iruka lost an eye and researcher Toomine Kanari died shielding Junko. This tragedy cemented her resolve to protect others and deepened her devotion to Shokuhou.

Her ability, Rampage Dress (Heavenly Garment Equipping), is classified Level 4. It manipulates bio-electrical signals within her cells to enhance physical capabilities: boosting muscle strength for superhuman speed and durability, sharpening olfactory senses, or accelerating neural processes. It offers no protection against self-inflicted damage from overexertion. Subconsciously, she limits her power to avoid endangering others, a restraint rooted in her Ideal trauma.

Her personality blends refined "ojou-sama" manners with fierce loyalty. She proactively supports Shokuhou without awaiting orders, such as restricting sweets to maintain her figure or intercepting unwanted interactions. Outside her social circle, she exhibits naivety, notably believing Shokuhou and Misaka Mikoto can reconcile and misunderstanding lewd comments. She shares Mikoto's enthusiasm for Gekota merchandise, owning themed underwear and struggling to choose between Gekota and Shokuhou when pressured.

During the Daihasei Festival, Junko monitored Shokuhou's diet and participated in Tokiwadai events. When Shokuhou acted suspiciously before confronting Kumokawa Seria, Junko mobilized the clique's network to track her, insisting on providing backup despite initial refusal. Later, Shokuhou summoned Junko for assistance against Mitsuari Ayu and the FIVE_Over model; Junko helped neutralize its operators, incapacitating a knit-hatted man supplying sensory data. She also aided in escorting an injured Kamijou Touma, though Shokuhou declined direct assistance.

Following Academy City's shutdown during the Coronzon conflict, Junko appeared alongside Shokuhou in Bali and later Tokyo. During the Acute Kotatsu Syndrome riots, she was affected while walking with Kobayashi. On New Year's Day, she accompanied Shokuhou to a shrine in School District 12, encountering Kamijou Touma's group and Sisters.

In the Astral Buddy sidestory, Junko investigated a "ghost girl" stalking her, revealed as Senya Yūri's astral projection. This led her to confront unresolved trauma from Ideal, including Iruka Yumiya's grudge over her sister Rakko's injuries. Junko reconciled with Iruka after a battle where both acknowledged their limitations. The investigation uncovered suppressed memories of Senya's role in the Ideal incident and Kanari's sacrifice, further solidifying Junko's commitment to atoning through protecting her current allies.