Jill, whose original name is Alektra Maria von Loewenherz, is a central figure in the world of Norma, serving as the supreme commander of the Arzenal base. Her background is one of profound loss and betrayal, as she was originally the First Princess of the Galia Empire. Upon being discovered as a Norma, an being unable to use the world's dominant Mana, her own father covered up her existence and exiled her to Arzenal, telling the public she had died of an illness. This personal history is the crucible in which her hardened worldview was forged.

In her early days at Arzenal, Jill was a different person: she fell into despair but eventually found strength and became a figure of hope, even becoming the first pilot of the legendary Para-mail, Villkiss. However, a disastrous deployment that resulted in the loss of her right arm, her entire squad, and her royal ring fundamentally changed her. After this trauma, her personality calcified into a calm, cold, and ruthlessly pragmatic demeanor. She often uses foul language and displays a cynical, sometimes sadistic, sense of humor. For instance, she cruelly echoed the protagonist Ange's own words about enjoying killing DRAGONs back at her when the truth about their enemy was revealed. She is known to be a smoker, and her right arm is an artificial prosthetic that hides a miniature freezing bullet gun.

Her primary motivation is a deep-seated hatred for the World of Mana, a society that rejected her and all Norma. This hatred fuels her grand plan, a revolt she calls "Libertus," which she has been secretly orchestrating for many years. Her goal is to overthrow the existing order masterminded by a man named Embryo. To achieve this, she is willing to use anyone as a tool, justifying her ruthless methods with the belief that she is "already in hell". She sees the exiled princess Angelise (Ange) as the key to her plan, as only a person of royal blood can unlock the full power of the Villkiss. Jill subjects Ange to harsh treatment, believing it will harden her into the weapon "Libertus" needs.

In the story, Jill begins as the authoritative commander of Arzenal. She is the one who reveals the truth of the world to Ange, exposing Embryo as the architect of Mana society and the one who made Norma scapegoats. When the Misurugi Empire attacks Arzenal, she initiates "Libertus, " leading the surviving Norma in an exodus aboard a hidden submarine called the Aurora. Her role becomes increasingly antagonistic as she takes hostages, like Ange's maid Momoka, and attempts to coerce others into serving her vendetta. She is haunted by her troubled past with the seemingly immortal Embryo, a man for whom she harbors a consuming desire for revenge. One of her most significant relationships is with Salia, a young pilot who admired her. Jill manipulated this admiration, acting as a sister figure to secure absolute loyalty, only to discard her when a more suitable pilot in Ange appeared, directly leading to Salia's jealous defection to Embryo.

Throughout the series, Jill's development is a tragic arc of a hero who fell from grace. Although she is a tough and capable fighter who proves adept in hand-to-hand combat and with firearms, she is also broken by her past failures and consumed by her need for atonement through revenge. While she initially succeeded as the first pilot of Villkiss, she cannot use it to its full potential, a limitation that defines her need for Ange. Her notable abilities extend beyond combat; she is a strategic and manipulative leader, capable of planning a multi-year insurrection. However, her rigid and cold leadership style ultimately creates enemies and fractures her own ranks. In the end, after being mortally wounded in her final confrontation with Embryo, she experiences a moment of clarity and reconciliation with Salia, admitting that the young woman was like a sister to her before she dies, a tragic end to a life defined by loss and a war against a god-like enemy.