Wikipedia:

Carmen 99 (real name, Carole Mendosa) is a bright and self-sufficient intelligence agent/mercenary who Van and Wendy encounters in the second episode of the anime, although Van appearently has met her before. The nickname 'Carmen 99', comes both from her bust measurement (99 cm) and the number of hidden accessories she always carries. Carmen grew up in the town of Trinolia with her uncle and his daughter (having lost her parents), both of whom she shared a close friendship with until she left the town. Throughout the series, Carmen frequently leaves Van and Wendy's company to later reunite with them, until she finally joins forces with them at the final stand to save the planet.