In the series, he will be given a Vemon-Killer Croc (Arkham Series)- Smaug (The Hobbit) persona. Somewhat like a hungry beast.  Look up videos of "Killer Croc Game Over Scenes", "Spiderman the Animated Series vs Vemon", and "Dragon Scene from The hobbit The Desolation of Smaug 2013" to get an exact idea of the type of voice range needed for role. 

 Gluttony is the embodiment of some of Father's gluttony. Often, he will be found eating a random person or creature's remains unless ordered to eat someone that poses a threat, or to remove evidence of the Homunculi's presence. He is typically in the company of Lust.