Etna was the King Krichevskoy's vassal before his death. Etna follows Laharl and Flonne before attempting to usurp the destined throne to Laharl, but then behind promise to become the skillful arm of the King. Money-hungry and despotic with her servants, the Prinnies, she uses a large hammer to hit them and her enemies.
In the end of the anime, she's given dominion over the netherworld and made queen by Laharl. However, both she and Fallen Angel Flonne are shocked when they find the new prinny, who she is about to scold for being a slacker, is none other than the reincarnated King Laharl.