Not much is known about she and her sisters' past life. Just that some time in their life, they ended up in an orphanage. Miss Hattie, the owner of the orphanage, was a strict ruler, being harsh with the orphans she was supposed to be taking care of. The three of them were forced to spend most of their days walking around selling boxes of cookies, only to be belittled by Miss Hattie upon their return to the orphanage, regardless of how well they did or didn't do. Every night they would pray for someone to adopt them. One day, they sold cookies to Vector, who, at the time, was competing against Gru in stealing the moon. Gru, who had just failed several attempts at breaching Vector's security, looks on in as the three girls are able to walk right into Vector's base. He thinks up a scheme to exploit the girls to steal the shrink ray, which was a key component in both villains' plans to steal the moon, and was in Vector's possession at the time.
Not soon after, Gru follows through with his idea and adopts the three girls, and they move into his dark house. While Agnes is ecstatic at having a new father, Edith and Margo are wary of him, though Edith, being a tomboy, finds many "toys" to play with at Gru's house, including an iron maiden and several weapons, accidentally disintegrating Agnes' unicorn in the process of playing with one of his weapons. At one point Edith asks, "What does this do?" and breaks a glass bottle containing a potion-like substance of some sort.