A Missionary of the Adeptus Ministorum, Father Zacharius serves as spiritual leader aboard the Final Offer. He is a famous firebrand whose sermons are a popular feature of shipboard life, attracting crowds of faithful (and bored) crewmen and filling them with the Emperor's zeal.

When preaching fails, he is able to call upon the services of a small number of Inquisitorial Acolytes to root out corruption, led by the Iron Evangelist Evgeny Valentin.