The girl who would one day be named Monstress lived a pampered life on the planet Xanthu in the latter half of the 30th century. Candi Pyponte-Le Parc III was born with pure white skin and had brown hair. She discovered that her beloved father had impoverished workers in his labor farms which numbered in the hundreds. She was shocked by this revelation, not agreeing with it and doing her best to rally for the workers. Candi's appearance was radically changed when a gene bomb exploded in one of her father's plants, transforming her into a green hued giantess. Discovering super strength and invulnerability, Candi adopted the name Monstress. As one of the few denizens of the planet with superpowers, she was quickly approached for and joined Xanthu's Uncanny Amazers. Monstress was then recruited into the Legion of Super-Heroes, as were her fellow teammates Kid Quantum and Star Boy, after a savage battle against the evil sorcerer Mordru.
Candi took on the big sister-type role towards many of the Legionnaires. Strong, compassionate, sweet, and honest, she'd lend a shoulder to cry on and an earful to those who were being rude and/or disrespectful towards others. She loved fashion and had a habit of changing her wardrobe, and would unintentionally drive the Athramites insane with her constant requests. In addition to being close friends with her fellow Xanthian Legionnaires, she formed a bond with the gentle soul of Element Lad. This was despite the fact he used his transmutation powers to change her green skin tone to an orange hue against her will. When Element Lad said she looked pretty in orange and now had an excuse to get a whole new wardrobe, Monstress quickly warmed up to the change.
Monstress had been off-planet on a mission when the Blight came to Earth and dismantled the Stargate system. Candi and her fellow Legionnaires spent the next month on a shuttle with limited supplies and each others company as they took the slow way home, finding Earth in ruins. She helped liberate the Earth from the Blight. Her helpful nature led her to being trapped on the Legion Outpost and lost in another galaxy with several Legionnaires as she had been holding up a hallway roof so others could escape. Being alone and hunted in a foreign galaxy tested even Candi's cheer and she relied on newcomer Shikari Lonestar to help keep her focus. She was overjoyed when the team eventually came across their missing teammate Element Lad, however he had become a changed man after being lost in both time and space. He had been alone for billions of years, his way of thinking greatly altered and believing himself to be the Progenitor of the entire galaxy. When he found out his old friend Monstress wasn't one of his creations, he deemed her a "variant" and killed her. Monstress was mourned by her teammates and a statue was erected in her honor on Legion World.
Monstress' physique and musculature were greatly augmented due to a gene bomb. Her new, Khund-like stature gave her super-strength, endurance, and a fair measure of invulnerability. She was shown to be able to lift an entire Legion cruiser single-handed and could survive a direct missile hit without a scratch to her skin. During periods of high emotion, these already stellar attributes were greatly increased.
As a member of the Legion of Super-Heroes, Monstress was also given a Legion flight ring, transuit, and telepathic ear plugs. The flight ring enabled Monstress to fly as well as provided communication and projection systems. Her transuit was a space suit that enabled her to breathe and exist in space, while her telepathic ear plugs allowed her to communicate in the vacuum of space mentally to others as well as translate foreign languages automatically.