Mary Ann was a gifted robotic engineer and a pacifist. Mary Ann tried to use her gift to help others by designing robots. One day the Drule witch Haggar stole her latest creation and turned it into a weapon. The theft of her latest robot was the last straw for Mary Ann, who vowed never to build anything ever again.
While on her way home Haggar had Mary Ann's stolen robot to try and capture her. The Voltron Force found and rescued her instead. Mary Ann came up with the idea to build a new robot to help stop Haggar. When the robot succeeded and Haggar was driven off by Voltron. Mary Ann decided to use her talents to help the Galaxy Alliance.
- Marry Ann is a character exclusive to the U.S. version of the Voltron: Defender of the Universe series.