Anoser was a Human woman who belonged to the Onderon Royal Family, and alongside her sibling Anosek, she was a relative of King Regalun Petryph of Onderon amidst the renewed Galactic War, a widespread conflict in the galaxy involving the Sith Empire and the Galactic Republic.
In the Onslaught Imperial narrative, the playable character receives the assignment to dispose of Anoser and Anosek, with the intention of provoking King Regalun Petryph to incite his followers against the Republic in an assault on the capital city of Iziz so that he might win back his throne. The player has the choice of either killing both of them or capturing them.
Although the destiny of the cousins remains unspecified in the Republic narrative, Lana Beniko suggests the cousins as possible successors to the throne after Petryph is overthrown, but expresses her disappointment that they lack the qualities needed for such a position.