He studied art at Saint Jordi and joined the military, where he stayed until 1957.
After leaving the military he joined the Spanish art agency Seleciones Illustrada and started working for various romance comics for companies like Fleetway and Valentine.
Mas was hired by American company Warren Publishing in 1972: he subsequently drew a total of 17 horror stories for their magazines Creepy and Vampirella until January 1975.
After leaving Warren, Mas moved to Venezuela and stopped his comic work, choosing instead to focus on painting.
This profile of a European comics creator, writer, or artist is a stub.