heir origins obscured by time, many patterns of weapon employed by the Space Marine Legions date back to the Dark Age of Technology or before. Weapons designated Proteus pattern share this unknown origin, in use since long before the coming of the Emperor and the Age of the Imperium.

The forebear of the later assault cannon, the Rotor Cannon was a multi barrelled stubber that could sustain an extraordinary rate of fire. Whilst lacking the power of bolt shells, the hail of fire produced by the rotor cannon could make short work of enemy hordes. Simpler to produce than most heavy