Mozgus is one of the chief Inquisitors of the Holy See, traveling the world with his group of torturers, sent to root out a violent cult of heretics in the city of St. Albion. He is the main antagonist in the Tower of Conviction, hindering with his excessive religious zeal, Guts tries to save Casca. His symbol is four torture wheels, embodying his willingness to use torture as a way to cleanse people from evil.

Mozgus, prior to the events told in the Resurrection Arc was a zealous Inquisitor, acting on behalf of the Holy See. There he recruited a small group of marginalized, disfigured individuals, comforting them by reading parts of the Holy See Doctrine, meant to reassure them that even their disfigurements were meant to be worn with pride as a gift from God, and training them in his particular brand of torture, vicious and rarely leading its survivors to walk away without serious wounds.

He is then sent to St. Albion to root out heretics on the behalf of the Holy See, requesting the Holy Iron Chain Knights as his personal guard. Albeit a true heretical group is brewing in the mountains surrounding St. Albion, based on orgiastic rituals, Mozgus himself apparently does little to stop them, managing to capture many of them only by Farnese's intervention. Instead, he sets every bit of his attention towards smothering in blood and tortures the rebellions of the poor and starving population of St. Albion against the tyrannical rule of the Holy See. Mozgus sees such acts of defiance against himself as defiance against God, whose rule he is meant to embody.

Physically tall and strong, harsh and demanding with everyone, even himself, he impresses Farnese by smothering several rebellions with threat of death and torture, sparing only a young mother asking more food for her starving child. Though Mozgus does give the child food and medical attention, he sentences the woman to torture with a tearful prayer that she survive the "test" that God has prepared for her, and attempting to use the encounter as a lesson to Farnese about the harshness of God's doctrine.

(Source: Berserk Wikia)