TV-Series
Description
Cal Devens, Judy Devens' younger sister, is an American teenager living near Los Angeles. Her life shatters when a shootout kills Judy with a stray bullet, leaving Cal orphaned and consumed by vengeance. She encounters Zwei (Reiji), misidentifying him as a vigilante, and uses stolen Inferno funds to hire him to kill her sister's murderer. Zwei tries to shield her from Inferno, fails, and takes her as his assistant to protect her.

Initially, Cal displays an optimistic and resilient personality despite her trauma. She is playful, stubborn, and fiercely determined, often frustrating Zwei with her persistence. Their bond evolves into a sibling-like relationship. After a life-threatening event, Zwei flees America believing Cal dead. Cal survives, feeling abandoned. The manipulative Inferno scientist Scythe Master exploits her grief and resentment toward Zwei, twisting it into hatred. He trains her as his third assassin, designating her "Drei."

Cal's appearance transforms drastically. As a teen, she has jade eyes and medium-length blonde hair often in high pigtails, wearing youthful clothes like a light purple skull-motif dress. Two years later as Drei, she adopts a mature biker aesthetic: long blonde hair in a high ponytail, a strapless black top, red jacket, fingerless gloves, and a red helmet, symbolizing her vengeful descent into assassination.

Her weapon skills, first cultivated under Zwei, become lethally efficient under Scythe Master. She adopts the codename "Phantom," echoing Zwei's former title. Her combat tactic involves a pocket watch Zwei gifted her, delaying attacks until its melody ends – a homage to classic westerns. The watch also becomes a memento of her grudge.

In the climax, Cal relentlessly hunts Zwei to settle her vendetta. He offers his life to spare Elen (Ein), fueling Cal's jealousy and rage. Their final confrontation ends with Zwei killing her; he places the pocket watch in her hands, later used as a distraction against another attacker. Her arc concludes with this death.

Across adaptations, Cal's quest for vengeance and assassin relationship parallels Mathilda from *Léon: The Professional*. She frequently recites lines from films like *Dirty Harry* and *Taxi Driver*, reflecting her immersion in violent media tropes.