When Momen was young, her father took out a loan from the InterGalactic Banking Clan to help the mortgage on the family farm. When bad harvests made him unable to pay it back, the Clan confiscated their holdings, requiring the family to move to the city. This led to her father's depression and eventual death, and left Reija with a lasting hatred of Muuns.
In 27 BBY, Reija was made chief administrator of the Intergalactic Communications Center, due to the fact she liked the job as opposed to the large salary. The workers at the Communications Center referred to her as "Momma Momen." She considered eventually retiring to start a family on Alderaan.
After being taken hostage by Pors Tonith during the Battle of Praesitlyn, Tonith used Momen to send a message to the Republic, demanding Republic forces evacuate Praesitlyn or the Separatists would start killing hostages. Momen read the message, but against orders, she ordered the Republic to attack. She was rescued by Anakin Skywalker, only to be shot by a battle droid and die in his arms, having shielded him from the blast.
Because of her physical resemblance to Shmi Skywalker, Anakin found himself reliving his mother's death. Momentarily tapping into the dark side of the Force, he proceeded to cut a swath of destruction through Tonith's security forces and nearly killed the Separatist admiral before being stopped by the spirit of Qui-Gon Jinn.
- Jedi Trial (First appearance)