Serving as the misguided enforcers of the Heretic Invokers, they lead small groups of raiding parties in search of sacrifical flesh for their unholy god. Ruthless and effective, they help ensure that there is always someone to sacrifice to their god, whether it is an innocent woman or one of their own.
They lead Heretic Worshippers and Minions, constantly harassing trading routes and unguarded villages, often succeeding in capturing prisoners. Unlike the worshippers, they are more often than not equipped with lethal runed weapons. This means that they are much more dangerous than most other Heretic troops. Donning an extremely strong coat of plates and riding on powerful Netherworld Chargers and Ironbred Chargers, they are a match for even the Knights of the Dawn.
Don't bother sending troops like Empire Legionnaires or Ravenstern Kierguards against them. The Heretic Magnus will easily slice them apart. Even polearm wielding infantry have difficulty fending them off. Fierdsvain Huscarl also have some difficulty overpowering them. The best way to get rid of them is to counter-attack with heavy cavalry or picking them off from a distance with archers or sharpshooters.
Another tactic some may use is to use a Great Hammer to land a hit even if the Magnus has a shield up. These slow, yet powerful hammers have sufficient power to knock a Magnus in one hit.