The Crozius Arcanum serves as both a sacred staff of office and a close combat weapon for Space Marine Chaplains. This duality is perceived as only natural to a Space Marine, who see battle as the most glorious form of worship to the Emperor.
The Crozius Arcanum itself is a staff of medium length, topped with the Imperial Aquila or symbols, such as winged skeletons or skulls. A few versions use iconography from the Chapter they belong to. The Salamanders, for instance, use the smith's hammer or a dragon's head. Ortan Cassius, Master of Sanctity of the Ultramarines, has fashioned his Crozius Arcanum after a Tyranid head, in remembrance of the Battle for Macragge.[Needs Citation]
Incorporated within the staff is a powerful energy field capable of disrupting matter much in the same way as a Power Weapon. At least one Crozius, the Stormrod used by Chaplain Carnak of the Imperial Fists, is capable of projecting its power field to strike down enemies from a distance.
Croziuses are also still used by the corrupted Dark Apostles of the Word Bearers, the only Chaos Space Marine Legion which still use Chaplains. However, the weapon is known as the Accursed Crozius, debased and twisted from its original form into an icon of worship for the Dark Gods. Not only is the Accursed Crozius still a potent weapon, it also signifies that the bearer is blessed by their patron God, enjoying physical protection as well as a closer connection to the daemons of the Warp.