|The information in this article comes from Dynamite's Warlord of Mars and is not written by Edgar Rice Burroughs.|
The Colossus is a gigantic green-skinned humanoid construct created on Barsoom by the Ancients. Its great power led to Voormenihes burying it within the catacombs of Lesser Helium where it remained dormant for countless years. They were able of bonding with a sentient host through tendrils from the forehead which led to a union between the two. Once bonded, the Colossus was a powerful weapon of destruction as its great mass and strength allowed it to batter targets easily. In addition, it was able to generate powerful energy blasts from both its mouth and hands that were able to decimate entire armies. The great resilience of the Colossus meant it was able to withstand a great deal of punishment without any apparent damage.
The Warlord of Yorn managed to uncover the existence of the Colossus and began excavation of it. In addition, he used the research of his son Valian as part of his plans at uncovering the machine. To trick his son, he arranged a marriage with Dejah Thoris though this was a smokescreen as part of his plans at uncovering the ancient machine. During a Green Martian assault at his city, the injured Warlord of Yorn went before the Colossus in anger at being unable to activate while his city was under siege. His anger activated the machine and he bonded with it whereupon the Colossus broke from the catacombs where it decimated the Green Martian army. When Valian betrayed him, Yorn's monarch faced an interference that led to a temporary paralysis and destabilization in the machine.
Afterwards, the Colossus was used to destroy all Yorn's enemies with three tribes of Green Martians wiped out while Red Martians who opposed him were wiped out as well. However, Valian was rescued by Dejah Thoris who developed an interference device which he activated before the Colossus. This led to it deactivating and being destroyed with the lord of Yorn dying as the great machine fell apart.