Etna is one of the major characters in the Disgaea franchise. She is the (abusive) leader of a squad of Prinnies and Overlord Laharl's closest vassal (which doesn't necessarily mean she's nice to him all the time). She is a manipulative, carefree, and somewhat immature person who doesn't always make it clear whose side she's on or what purpose she's working toward. Despite physically looking like a young teenager, she is actually over 1400 years old.
For the first Disgaea game, Etna was voiced by Amanda Winn-Lee. Since Amanda took time off from voice acting in the mid-2000s to take care of her leukemia-diagnosed son, Etna has been voiced by Michelle Ruff in all of her other appearances (including Hour of Darkness's PSP remake).