The Vindicator has been in use by Imperial forces since the Great Crusade, and it has hardly changed since those turbulent days so long ago. The Space Marine Legions that sided with the corrupted Warmaster and Primarch of the Luna Wolves, Horus Lupercal, used their Vindicators against the Loyalist forces of the Emperor during the Horus Heresy. After the Horus Heresy ended in a pyrrhic victory for the Emperor’s Loyalists, the Traitors fled into the Eye of Terror, and luckily the number of Vindicators they still have in their possession is quite low in the late 41st Millennium, due to the Traitor Legions’ inability to easily replace their losses.