Lydda Jath, alias Night Girl is a native of the planet Kathoon, a world which is in perpetual darkness, heated by an internal power source. Lydda has super strength, given to her by her scientist father, but only at night or in deep shadow. 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 welcomed new recruits. 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 metahuman powers . He took almost a year to perfect a serum that once ingested would give them enhanced abilities. 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 super strength.
When she came to Earth, she eagerly awaited to audition but once in front of the Legion her powers failed. It was revealed her powers are negated by Ultra-violet radiation. She was rejected 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..
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 Kathoon after Cosmic Boy re-formed the Legion. 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 was destroyed.
- Superhuman Strength: Night Girl has the powers of super-strength, equivalent to that of Superboy or Mon-El lift far in excess of 100 tons, but only in darkness or deep shadow.
- Superhuman Stamina: Night Girl could sustain prolonged physical exertion without tiring or undo strain for an indeterminate period of time, but only in darkness or deep shadow.
- Ultra-Invulnerability: When using this power, she is impervious to harm by extreme forces. If propelled at sufficient force, by either her flight ring or a super-toss, can use her dense body like a human missile, but only in darkness or deep shadow.
- Hand-to-Hand Combat (Advanced): 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.
- Ultraviolet Negation: Her powers fade immediately in the presence of direct sunlight. Her powers can be negated by the presence of ultra-violet energy.
- Darkness Bombs At first Lydda carried darkness bombs from time to time which allowed her to use this strength while in close proximity during a melee.
- In the Possible Future stories of the Adult Legion, Night Girl (now Night Woman) and Cosmic Man are married, and have a child.
- Adventure Comics (Volume 1)
- Adventure Comics (Volume 2)
- Final Crisis: Legion of 3 Worlds
- Legion Lost (Volume 1)
- Legion Lost (Volume 2)
- Legion of Super-Heroes (Volume 1)
- Legion of Super-Heroes (Volume 2)
- Legion of Super-Heroes (Volume 3)
- Legion of Super-Heroes (Volume 4)
- Legion of Super-Heroes (Volume 5)
- Legion of Super-Heroes (Volume 6)
- Legion of Super-Heroes (Volume 7)
- Legion Worlds (Volume 1)
- Legionnaires (Volume 1)
- Superboy (Volume 1)
- Superboy and the Legion of Super-Heroes
- Supergirl and the Legion of Super-Heroes
- The Legion (Volume 1)
- 96 Appearances of Lydda Jath (Pre-Zero Hour)
- 21 Images featuring Lydda Jath (Pre-Zero Hour)
- 1 Quotations by or about Lydda Jath (Pre-Zero Hour)
- Character Gallery: Lydda Jath (Pre-Zero Hour)
Legion of Super-Heroes member