Anne is a young girl with red hair, red eyes, and scars on her nose and right cheek, a result of experiments at the Berühren Corporation facility alongside Tetsuro Arahabaki and her sister Ende. Her personality centers on profound devotion to Ende, whom she fiercely protects. To ensure their survival, Anne agreed to carry out Berühren's missions, including attacking children to lure Tetsuro. She rationalized their existence as tools, believing compliance offered their only chance for shared happiness.

During a mission, Anne and Ende fled Kyusei Group assassins when Tetsuro intervened via Juzo Inui's body. Anne directed Ende to transform into a spider-like Extended, motivated by Berühren's promise to restore Ende's body upon success. She rejected Tetsuro's offer of escape, insisting Berühren was their home. Ende's paralyzing poison attack incapacitated Tetsuro, but she lost control and rampaged until Anne stabilized her with their established calming gesture: holding her hand.

Later, Hugh Cunningham threatened elimination for their failure. When Tetsuro intervened again, Cunningham ordered Anne to seize Tetsuro's body and Ende to kill Juzo. Anne defended their role as tools, declaring it preferable to death. Ende resisted and reached for Anne. Cunningham then injected Ende with a transformation-inducing drug. In the ensuing chaos, an enraged Ende accidentally struck Anne. Mortally wounded, Anne confessed guilt for pushing Ende and pleaded with Tetsuro to save her sister before dying. Ende was subdued by Juzo and Tetsuro, then rehabilitated by Mary Steinberg, who removed her dangerous modifications. Anne's story concludes with her death, leaving Ende to rebuild her life alone.