Lucifer is introduced as the main antagonist of the story and one of the three Hunters, a group of psychic beings awakened to destroy anyone they consider unjust in the world. Among the Hunters, she is consistently described as the most powerful and the most fanatical. Her background as a Hunter is defined by a singular, extreme sense of purpose: the absolute elimination of injustice as she perceives it. This mission overrides any other consideration, and she pursues it with ruthless efficiency.

Her personality is characterized by unwavering fanaticism and a complete lack of mercy. She shows no regard for collateral damage or innocent lives, viewing anyone who aids or shelters her targets as equally guilty. This is demonstrated when she causes a massive highway pile-up solely to capture a single individual, Tachihara, and kills anyone, including Special Service agents, who attempts to help the Red May terrorists. Her sense of justice is warped and absolute, making her an indiscriminate and terrifying force.

Lucifer's primary motivation is the execution of her perceived duty. She believes she has been sent to cleanse the world of the unjust, and she pursues this mission with a single-minded intensity that borders on obsession. Unlike her fellow Hunters, Asura and Freya, she does not question the morality or consequences of her actions. She is driven purely by the need to fulfill her purpose, regardless of who stands in her way.

In the narrative, Lucifer serves as the ultimate physical and psychological threat to both the Red May terrorists and the Special Security Force. Her actions force the main characters to escalate their own tactics and technology. She systematically eliminates key figures from both sides, including wiping out the Red May members and killing several members of the Special Security Force, such as Hacker, Peace, and Kuwata. The entire final conflict of the series revolves around the need to stop her, culminating in a direct confrontation with the cybernetically enhanced Raiden. This confrontation ends with Raiden sacrificing himself by detonating his powered suit in front of her, which finally destroys Lucifer.

Her key relationships with the other Hunters highlight her fanaticism. Asura, another Hunter, initially shares her goals but eventually turns against her after seeing her methods go too far, recognizing that she has become a greater threat than the people they were meant to punish. Lucifer also kills Freya, the third Hunter, showing that she will eliminate even her own kind if they oppose or interfere with her mission. She has no alliance or loyalty outside of her own absolute code.

Development is minimal for Lucifer; she does not change or waver throughout the story. She remains a static and implacable antagonist, driven by her unwavering conviction until the moment of her death. Her role is to embody an unstoppable, amoral force of judgment.

Lucifer possesses formidable psychic abilities, primarily telekinesis and telepathy. She can manipulate objects and people with her mind, lift and throw vehicles, and control the bodies of others, as seen when she takes over Hacker's body and forces him to detonate a grenade. A unique aspect of her power is her ability to increase both her physical and psychic strength by absorbing electricity, making her even more dangerous when she has access to a power source. She also demonstrates the power to drain the minds of others, effectively killing them psychically. These abilities make her nearly invincible against conventional opponents and require a drastic sacrifice to finally overcome.