Gruntus Poobah is the leader of the Brotherhood of Grunt. He resides with his brothers at The Monastery and presides over matters, such as cultivating cheese, holding the Grunt Games, initiating new members into the Brotherhood or finding hatchlings in the warts of the species proginator: the Primus Gruntus Maximus.
He is usually attended to by his aide, Ringo, who prepares martinis for him and carries him around on his back.
He is the only Grunt shown to be able to speak intelligibly, at least to the audience.
In The Ceremony he is initiating the Brothers Grunt into the Brotherhood, and has a flashback to the day of their hatching. As he is initiating the brothers using the "Placing of the down", (rubbing a duck's butt against their faces) he notes Perry as the Chosen One and crowns him as such, putting him on a golden toilet.
However, Perry refuses his responsibility and runs off, and Gruntus Poobah tasks his five brothers to find him, because "without the guidance of the Chosen One, the Brotherhood will fold".
In Black Balled Grunt it is revealed he once took a human child left at his doorstep into the Monastery, and named him Vince. However Vince refused to live at peace with his brothers, and even tried to have the Gruntus Poobah chased from the Monastery, under the pretense that the Brothers would never eat cheese again. However, he was stopped and thrown out himself by Ringo.