Yuka is linked to Shouji's abduction, having lured him to a party where he is drugged and violated by a group of women. After surviving abandonment, Shouji tracks Yuka to her home. He impersonates a delivery person, gains entry, overpowers her, and imprisons her within a cardboard box.

This encounter violently reverses Yuka's position. She shifts from an initial participant in Shouji's trauma to a captive under his control. He rapes her, enslaves her, and forces her into his revenge scheme. Acting under Shouji's command, her role becomes that of an accomplice. He deploys her as bait to contact other women involved in his assault.

Yuka procures compromising photographs and personal information on the targeted women, supplying Shouji with the means to trap them. Her participation includes enabling their capture, confinement, and public exposure, fulfilling Shouji's plans for retribution. This places her within a cycle where her victimization leads directly to complicity in coercing and harming others connected to Shouji's ordeal.

Her history before these events and eventual fate remain unrecorded.