TV-Series
Description
Kurumi is a young female character of unknown origins who ran away from home at an early age. She operates as a prolific hacker under the alias "Walnut," derived from the Japanese meaning of her name. References to the alias having "died multiple times in the past 30 years" contrast with her youth, suggesting Walnut might be an inherited title. Her hacking activities included a major contract with Shinji Yoshimatsu to extract intelligence from the DA organization's Radiata system. After completing this job, her questioning of Yoshimatsu and the Alan Institute's motives led to the destruction of her condo and an attempted assassination. Rival hacker Robota disclosed her assumed location in an attempt to dethrone her as Japan's top hacker.

To ensure survival, Kurumi, as Walnut, contracted Café LycoReco for protection. Wearing a full squirrel costume for anonymity during transport, their vehicle was remotely hijacked by Robota, leading to a confrontation with armed mercenaries. Ambushed in an abandoned store, the individual in the squirrel costume appeared killed. It was later revealed Café LycoReco employee Mizuki Nakahara wore the costume as a decoy, equipped with bullet-proofing and fake blood to fake Walnut's death. Kurumi emerged unharmed from a yellow suitcase Mizuki carried, having orchestrated the deception to mislead Yoshimatsu and Robota.

Granted refuge at Café LycoReco in exchange for work, she initially introduced "Kurumi" as another alias and spent most free time on a computer inside a café closet. Characterized as a reluctant employee, she looked forward to gaming parties with the café's regulars. She provided technical expertise for LycoReco missions, successfully upscaling a photo to identify participants and timing for an arms deal aiding Takina Inoue and Fuki. Later, during the escort of Matsushita and thwarting of Jin, she took a more involved role as mission control.

In the spin-off short animation "Friends are thieves of time.," Kurumi appears in episodic narratives focused on Café LycoReco's daily life. In Episode 4, "Watch out!," she participates in a prank orchestrated by Chisato Nishikigi, Mizuki, and Mika to scare Takina, successfully triggering Takina's startled reaction. Her return after an absence was noted as a highlight for fans. Her enjoyment of gaming parties with café regulars, established in the main series, remains consistent in these slice-of-life scenarios.