The Mk4 'Maximus' Power Armor is a power armor set in Space Marine multiplayer. It is unlocked by achieving experience level 41 in multiplayer.
Issued toward the closing centuries of the Great Crusade, Maximus-pattern armor was still being deployed to Space Marines when Horus led half the Legions into heresy and revolt. At the time, this armor was intended to be the final and ultimate suit of armor worn by the defenders of man, and was the first suit of armor to incorporate many of the advancements made by the rediscovery of the disparate knowledge of the newly reunited human worlds. It was also the first suit of power armor to take on a shape recognisably similar to more recent models.
As many of the Mk4 suits were taken by the traitor legions during the heresy, and all previous armor marks were in the process of being decommissioned at the time, Maximus-pattern armor is extremely rare, but also among the oldest suits of power armor likely to still exist in complete sets during the 41st millennium.
A reminder of the bygone days of the height of Imperial glory, Mk4 'Maximus' armor is commonly preserved, to whatever degree possible, for posterity and 'as-is', with little or no modification to its original design. To be granted the use of even a single piece of preserved Maximus armor, let alone an entire functional set, is among the highest of honors in many Chapters.
- Chapter Champion: Achieve Level 41 in Multiplayer (Mk4 Power Armor)