In the 30th-century heroine called Night Girl was a native of the planet Kathoon which belonged to the United Planets Federation. Her world which was in perpetual darkness, the natives having adapted by having it heated by an internal power source. Lydda was the only child of one of Kathoon's leading scientists, and grew up given his utmost attention and Lydda was very close to him. When Lydda became a teenager the newly debuted Legion of Super-Heroes entered the galactic scene, welcoming new recruits from all U.P. planets. Lydda idolized the Legionnaires (particularly Cosmic Boy, on whom she harbored a secret crush) and longed to become a member, so Lydda's father devised a brilliant idea to grant his daughter meta-human powers and have her join the Legion as Kathoon's representative. He took almost a year to perfect a serum that once ingested would change the living beings D.N.A. to its core, effectively giving its user superpowers. Lydda was more than eager to please her dedicated father, and although at first scared, she took the vial of serum from her father and ingested its liquid. She successfully exhibited the unique and powerful meta-human ability of great super strength, however only at night or in deep shadow. Her powers were negated by the presence of ultra-violet energy and as a result she unsuccessfully tried out for the Legion of Super-Heroes, who rejected her on the basis that a power that only worked in darkness was considered impractical. Devastated by the rejection, Lydda left the tryouts, trying to figure out how to tell her father.
Night Girl created by Edmond Hamilton and John Forte.
Lydda soon met fellow Legion reject Polar Boy, who told her of his idea to form a secret reserve Legion team composed of other rejected heroes like themselves. As Night Girl, she became one of the founding members of the Legion of Substitute Heroes. The five-member Subs voluntarily took on lesser tasks that the Legion was too busy to handle, at first suffering failures, followed by mixed results. The team was often the butt of jokes and comic storylines, with Night Girl the only member that managed to keep her dignity throughout. The Substitutes were finally recognized by the Legion as a valuable asset after the Legion regulars were defeated during the assault on the Citadel of Throon. Night Girl and Polar Boy successfully led the Substitutes to a victorious attack on the fortress, lifting the siege. The Substitutes were granted Legion flight rings and official reserve status shortly afterward. During her time with the Substitutes, Night Girl worked hard to offset having powers with such a drastic limitation. She extensively developed her combat skills and soon became a highly-skilled martial artist. As a Sub, Lydda still harbored a major crush on Cosmic Boy. Eventually Cosmic Boy noticed her as well the two began a long-term romantic relationship.
Five Years Later
Five years later after the Magic Wars, Night Girl and Cosmic Boy got married and had a son named Pol Jath Krinn (in honor of Cosmic Boy's fallen brother). The couple settled on Lydda's home world of Kathoon after Cosmic Boy re-formed the Legion of Super-Heroes. She found herself in action once again, alongside the Legion against Mordru and Glorith, but soon afterwards, their timeline was destroyed by the Zero Hour. Thanks to the Time Trapper, Lydda survived to kiss Rokk one last time before existence faded to white.
Reboot / Earth-247
In this continuity Night Girl made two very brief appearances, as she was rejected at a tryout once again and joined the Legion of Substitute Heroes once more. In a nod to the previous continuity she noted that, had she been aware Cosmic Boy was on a secret mission, she might not have even made the attempt. She was seen in one panel in a later issue as she and Polar Boy talked about how the Substitute Legion had a long way to go until they were ready to take on a mission.
Threeboot / Earth-Prime
Night Girl made an appearance during tryouts as a Legion hopeful. She gave an impressive demonstration of her strength in a sparring match with Ultra Boy, but was rejected (as in previous continuities) on the grounds that her power only worked in darkness. Shadow Lass was her strongest supporter, pointing out that her own ability to create darkness could perfectly compliment Night Girl's power. Night Girl was then offered a position on the Legion Reserves, which she gratefully accepted.
Retroboot / New Earth
The events of the Infinite Crisis brought together the Legions of all three continuities, and restored a close analogue of before Magic Wars. Night Girl wore a modified version of her original costume, with revealing openings in the 'eyes' and 'beak' of the owl logo in her chest. In current continuity, Night Girl has finally achieved her dream of becoming a full member of the Legion, though she had never achieved that status in previous continuities.
Major Story Arcs
Powers and Abilities
Night Girl is a genetically altered meta-human who has the power of extremely great super-strength, equivalent to that of Kryptonian-level beings like Mon-El or Superboy, but only in darkness or deep shadow. Her powers fade immediately in the presence of direct sunlight or even ultraviolet light. She originally carried darkness bombs from time to time which allowed her to use this strength while in close proximity during a melee. Night Girl has learned other tricks to curb the weakness of her meta-human powers, and usually uses darkness as a key element of surprise in several mission tactics. Coming from a world without sunlight, Night Girl has no problem seeing in complete darkness. In her early appearances she was written as having X-ray vision, but this ability has not been shown in more recent continuities.
Since her powers are often unavailable, Night Girl has gone through intense training in several martial arts styles, taking another more direct route to level the table. By mixing her great superhuman strength along with a variety of effective martial arts moves, she has become a formidable combatant in most arenas.
Night Girl also wears a Legion Flight Ring, originally a gift from the Legion of Super-Heroes to all of the Substitute members. This ring acts on the users willpower to activate its flight capabilities and allows its user reasonable speed while in flight. It also acts as a mini computer and provides the wearer with maps, communications, and navigation capacity. In early appearances she (or a teammate) has carried devices that temporarily negate light so she could use her powers.
In future stories of the adult Legion, the two are still shown as being married with a child, though they had changed their code names to Night Woman and Cosmic Man.