The Repo Girls (ダーク・ガールズ; The Dark Girls) are a trio of illegal scrappers who make money from illegally disposing of robotic waste. They only appear in the episodes "Dragon Lake" and "The Case of the Phantom Fowl" in the 2003 series.
The Repo Girls primarily deal in disposing of older robots and their obsolete fuel. This fuel, IS-13, is flammable and becomes increasingly poisonous with age, and can disable a modern robot's circuitry. The Repo Girls provide an off-the-books, cheaper alternative to safe and legal chemical disposal. They have been known to simply dump old fuel canisters, raw fuel, and outdated robotics in nature and abandoned places. They have little regard for nature, and only work with the widest profit margin in mind.
The trio is made up of Christine, Sarah Jones, and Carla. While Sarah has another job and a life outside of the Repo Girls, it is unknown what Chris and Carla's real identities are.
The Repo Girls have access to a large amount of robotics and technology, which they use for their own benefit. They have previously set up hideouts under the Dragon Lake forest administration, and in the haunted house of an abandoned amusement park.
At one point, they had enormous weaponized beast mechas that could shoot out IS-13 and other hazardous material. These were used both in disposal jobs and in fighting Astro.
Sarah also has a large, robotic red serpent named Narga, and an improved version named King Naga. King Naga was capable of shooting a wormhole generating beam from his mouth. The Repo Girls attempted to fill this wormhole with garbage, believing that it was completely untraceable disposable, but they were unaware that they almost caused a collapse of space and time.