The Prinnies are souls of sinners that have been given the bodies of penguin-like creatures. They now work for demons or angels in order to pay of for the sins they have committed so that they can go to the Red Moon where they will be free. Most Prinnies are slaves and servants for Demon Lord Etna. They are also know to commonly say the word "dood" at the end of a sentence or when they are scared.
Prinnies are not very loyal to the masters that they serve and in most cases they only obey when they are payed well, beaten or threatened. The pouch that they keep on the belly is meant to store money as well as a large arsenal of weapons such as swords, guns, bombs and lasers.
Due to the Prinnies popularity among the fans of Disgaea, NIS made an adventure-game called "Can I really be the hero, dood?", starring a Prinny who has been ordered by Etna to find some stolen candy. there is also a sequel, where the Prinny has been ordered to find Etna's stolen panties.