Young Marcus showed an almost unnatural interest in the Imperial Faith, the history of the Imperial Saints, especially Sebastian Thor, and had a natural talent as regards different Low Gothic tongues. Mathematics and sciences, as far as they were taught on the Schola, deterred him. All this made him a perfect candidate for the Imperial priesthood.

At the age of 21 Marcus Luthor was assigned Preacher of the Imperial Faith and transferred to the 41st Al-Arach. His former mentor at the Schola gave him a copy of the Teachings of Sebastian Thor as a present, as well as a huge broadsword.

Upon his arrival on Tyanos, a small world in the Cthonia system, Marcus was assigned preacher of the 3rd squad of company four. In respect of the preacher's status the Sergeant of the squad, like all of his men deeply rooted in puritan tradition, organised Marcus a double-barrelled shotgun from the Captain's personal ammunition crate.

After 2 months of heavy fighting with secessionist forces, Marcus and his squad awarded the Imperialis 1st class for holding an enemy firebase for seven hours until relief troops could arrive. Three weeks later the campaign was completed successfully.

Marcus returned to the Schola on Moon and was elected drill abbot. After twelve years of teaching young progena how to fight, Luthor was offered to succeed late Sebastianus Allister, the Preacher of the Artemis chapel inside the High Inquisitorial Academy of Io. He accepted.

The young Aspirant Inquisitors of those days remember him as 'old gristle', faithful but bad medicine, puritan but complicated, usually murmuring prayers but in the next second preaching at the top of his voice. Incomparable, unique, peerless.

However Marcus Luthor took care of young Julian Kreider, or 'Fry' as the psyker was called in those days, made him get rid of his Dante's Landing Low Gothic gibberish, taught him in High Gothic and introduced him, very much to the displeasure of Inquisitor Tyrus, into the Amalathian ways.

Marcus became Fry's mentor and over the years a deep friendship developed.

When Fry …sorry, Julian… was finally elected Inquisitor, Marcus saw his last opportunity to leave the boredom of Io and explore the depths of space. He managed to be elected Missionary and accepted the symbol of his rank, the Iron Halo. The hilt of his broadsword was upgraded with a small power field projector shaped like the Missionarium sign.

He took an ancient tome from the library of the Artemis chapel with him, the Apocrypha of Acanon, containing a report of the Emperor's most famous sayings: “The bloods of Martyrs is the seeds of the future of Mankind”. Marcus fixed the tome on top of his missionary staff and followed Inquisitor Julianus to his first investigation.