Erika Arendt is a Jewish teenager with blonde hair and blue eyes. She possesses a photographic memory central to her survival. As the sole survivor of her family exterminated by the Nazis, she becomes a pursued refugee. Her mind holds "The List of Hope," a catalog of paintings hidden from the Nazis, making her a target for their recovery. Later, it is revealed she also memorized the secret designs for the atomic weapon "Tentei's Thunderbolts" (天帝の雷). This dual knowledge intensifies her pursuit by the Nahash organization, which designates her their "migdol" or tower.

Finding refuge in Shanghai under Liu Feiyan's protection, they develop a bond as Feiyan grows fiercely protective, ultimately sacrificing his life defending her. Erika grapples with profound grief and guilt upon learning his final wish was for her to abandon revenge.

Her connection to Yasaka forms when both are kidnapped by antagonists seeking the thunderbolt secrets. Confined in an underground palace, Genesis leaders reveal the full truth about "Migadol's Thunderbolts" to her. Yasaka risks his life to shield Erika, resulting in him being crushed by debris during the palace's collapse.

Later, she interacts with Ramon Kasumi, who acts as her temporary guardian during escapes from military forces. Her memories of jewels worn by Yasaka uncover their past significance. She confronts Kasumi Kenshin (formerly Himuka), who seeks to wield the thunderbolts for global destruction. Steeling her resolve, she approaches Kenshin directly, and they vanish together in a sudden gust of wind.

Her story concludes as she prays at Feiyan's grave, reflecting on Yasaka's fate, embodying quiet resilience after enduring profound trauma and loss.