I like the Imperial knights, I really do. But being a uniquist how would you feel about about a Megarachinid army? Not sure what those are? They were "exterminated' in 30k by the Blood Angels, the Luna Wolves and the Emperors Children.
"During the Great Crusade, the 140th Expeditionary Fleet discovered Urisarach (dubbed "One-Forty Twenty"), and, ignoring the Interex's orbital warning beacons, descended to the surface to effect compliance in the name of the Imperium. Then all contact with the 140th ceased, save for a lone distress call from Blood Angels Captain Khitas Frome, which ended "This. World. Is. Murder".[1x]
The Imperial forces that responded to the distress call included the 63rd Expeditionary Fleet under Warmaster Horus, a detachment from the Emperor's Children under Lord Commander Eidolon, and a relief force from the Blood Angels, led by Sanguinius himself. The war on "Murder" as it was dubbed, took several months, and all three forces suffered serious losses, but eventually the Megarachnids were exterminated.
The Megarachnids possessed long sword-like claws which appeared to be made from an organic metallic substance, and lived and worked in large swarms.
Their bodies were heavily augmented through a technological or biological process that, according to Captain Saul Tarvitz, made it impossible to discern where their bodies ended and their weapons began.
Well?