This armour is created by the Space Wolves Chapter's Iron Priests ( Techmarines) and officially codified by the Adeptus Mechanicus as the Mark XII Lupio Pattern, though the suits can look like any of the standard patterns of power armour described above, though because of their antiquity, many of these suits are earlier patterns than the Mark VI. The many different Loyalist Space Marine Chapters of the present utilise all these different power armour patterns in differing ratios. Some choose to equip their Astartes with the most advanced patterns of armour available to them, while others cherish the older patterns and seek to maintain them for as long as possible in a combat-ready state. Primaris Space Marines now wear modular Mark X Power Armour. This highly flexible protective system can be modified and upgraded to suit the needs of the battlefield. Mark X Tacticus Power Armour is the most common Mark X variant, and is worn by Intercessors, among others. Primaris Librarians replace their standard Mark X Tacticus Pattern raiment with Mark X Phobos armour when utilising the most subtle and illusory of their psychic powers, which rely on misdirection. The suit uses a heavily armoured helmet with sloping plates designed to deflect shots to the left and right, thus inspiring its name as the Iron Pattern. This helmet pattern inspired the later Mark IV and VI helmet designs. The wedge-shaped helmet also formed the basis for the later distinctive Corvus Beak helmet of the Mark VI pattern.

Whilst standard patterns of armour were shared across the Space Marine Legions during the Great Crusade, variations on these templates surfaced in most of the Legions.The Mark VI was first deployed during a two-standard-year engagement in the Great Crusade through a sector of space claimed by the remnants of the broken Aeldari race known as the Scalland Campaign. The Scalland Campaign was to serve as the original field test for the first thousand sets of prototype power armour that would later come to be designated as Mark VI; though at the time it bore the provisional designation Mark V since the later Mark V Heresy Pattern was a response to battlefield conditions. A Primaris Space Marine Intercessor of the Ultramarines Chapter wearing Mark X Tacticus Power Armour.

Mark VIII armour was an adaptation of Mark VII armour, both in the lore and in real life. It was actually the third suit of power armour to be designed, though among the last to appear as a miniature. Reinforced Vambrace - Primaris Space Marine sergeants, lieutenants and other officers incorporate communication cogitators. However, even a single shoulder plate or gauntlet that has seen millennia of service and countless battles is a treasured relic of a Chapter that brings much honour to the Astartes who has earned the right to wear it. With full production not yet begun on Mars and in the absence of reliable Legion supply lines, the ancient Mechanicum had designated all non-standard or stop-gap designs of power armour as the Mark V "Heresy" Pattern. Many of the improvisations made by the Raven Guard's armourium after the massacre were passed on to other Legions in the absence of replacement parts for the Mark IV suit. The equipping of the Legions with Mark IV armour was only partially complete when the Horus Heresy broke out. Many of the newly-equipped Legions turned against the Imperium while many of the Loyalist Legions still possessed only Mark II Crusade Power Armour. With the extensive amount of war damage and constantly mobile operations that defined warfare during the Heresy, resupply for the Loyalist Space Marine Legions' damaged equipment was difficult or impossible.

For the battle-sisters of the Calixis Sector, this helm is issued only after they have proven themselves worthy of wearing it. This armour was ideally used by Space Marines when cover was minimal and combat was a matter of a simple frontal assault. Because of this pattern of power armour's great strength, it became known as the "Iron Armour" or Armorum Ferrum in Imperial High Gothic. The Mark VII armour is characterised by the grim-looking Vox-caster (external vocalizer) on the faceplate, and the plastron displaying the Imperial Aquila or the Space Marine honour known as the Imperialis (a winged skull), which has given the armour different names such as Armorum Impetor ("Eagle Armour") or "Aquila Armour" ("Aquila" being the name of the two-headed eagle which symbolises the Imperium of Man). This habit of gaining information about a situation by scent is so natural to the Space Wolves that many feel slightly disoriented and claustrophobic when forced by circumstances to don their helmets.