A mysterious breed of Giant Creatures that fall from the sky like meteorites. Their bodies contain more Energy Gems than other Giant Creatures, so their eradication is given a higher priority by EDF Command; however, their rabid ferocity and agility, combined with enough battle power to down a building with a single strike, have made carrying out this order extremely difficult.
At EDF Canada, where the Sideros creatures were first encountered, many extermination squads formed with the goal of receiving bountiful rewards from their Energy Gems. While some Energy Gems were retrieved, the death toll has been exceedingly high, with EDF Canada losing 60% of their forces in a mere 2 days. Analysis of their corpses has found nothing resembling internal organs in their torso area, but large amounts of Energy Gems are stored in what appears to be arms.