At first, he was a Centurion, but was lured into a temple, the Forbidden City, by the voices of the Ancients. He fought his way into the temple and soon found a room containing the Claw of Chattur'gha, the Sigil of Xel'lotath, and the Veil of Ulyaoth. When the player chooses an artifact for him to touch, it corrupts him, turning him into an undead monster. In this form, Pious was immortal and a very powerful warlock who worked tirelessly to summon his Ancient into this world.
Throughout the game, while trying to summon the Ancient, he sent the dancer Ellia to oblivion after binding Mantorok; he later disguised himself as a warlord, sacrificing people to the Pillar of Flesh, including Roberto; he later disguised himself as a monk named Phillipe Augustine, trying to frame Paul for killing a monk named Brother Andrew; lastly, he later disguised himself as Paul Augustine to find the City Temple along with Edwin Lindsey (whom he attempted to kill, but failed miserably).
At the end of the game, Alexandra Roivas fought Pious, after summoning an Ancient to fight and destroy Pious's Ancient. With the help from the ghosts of the victims of the Eternal Darkness (Ellia, Anthony, Karim, Max, Paul, and Roberto), his Ancient's essence was destroyed, along with his barrier, and Alex defeated Pious, gravely wounding him. She then took his staff and stabbed him in the chest with it, killing him, although not before he ominously inferred that "[Pious's] death is only the beginning."