Valvatorez, a former tyrant, is a Prinny Instructor in Hades. Along with his servant Fenrich, he trains Prinnies before they are sent to the Netherworld or Celestia. During one of his graduation ceremonies, the Prinnies were mysteriously kidnapped by an unknown force. Due to Valvatorez's promise to the Prinnies (he would give each of them a sardine for graduating) he must find them in order to fulfill his promise. Fenrich, who has his own goal for Valvatorez, suggests searching for the one man with enough power in Hades to do this, thus setting the events that will change the Netherworld in motion.
Valvatorez confronts many challenges throughout his mission, which changes according to what he believes. At first, his mission was to rescue the Prinnies in order to fulfill his promise. However, this required him to rebel against the Warden of Hades, and ultimately, The President himself, as he issued the order to exterminate Prinnies due to overpopulation.
After rescuing the Prinnies and facing Emizel, Valvatorez begins to question the corrupternment's methods (such as exterminating prinnies) and why the Netherworld is collapsing into such overpopulation. When he later confronts Fuka and the Prinny X-Terminators, he is convinced that the corrupternment is trying to start a Prinny civil war and are only hiding behind their orders whilst reassuring the public, therefore causing him to start a coup to overthrow the corrupternment.
Before he lost his powers, Valvatorez was a powerful demon feared as The Tyrant. While Tyrant Valvatorez only appears in Cutscenes, a DLC scenario features Valvatorez in his Tyrant days and his first meeting with Fenrich. Upon completing the scenario, Tyrant Valvatorez is unlocked and can be used any time the player wishes, acting as a separate character to standard Valvatorez (similar to Archangel Flonne and Fallen Angel Flonne).
- The song "Arcadian Vampire" acts as the theme song for Valvatorez. Arcadian Vampire acts as the song for the player's base after Chapter 3 is cleared but can be changed to something else once the Music Store is unlocked.
- Valvatorez is the first Disgaea hero that does not have a bad ending from killing too many of his team mates. This is due to the ally kill counter being taken out since none of the endings require ally kills.
- Including Adell, Valvatorez is another demon who, unlike other Disgaea protagonists, keeps his promise until they are fulfilled without backing down from a challenge or resorting to dirty tactics to win.
- Different characters have made nicknames for Valvatorez, Fuka calls him Valzy (Fenrich as Fenfen), Fenrich calls him Lord Val and Artina calls him Mr. Weirdo at times.