The Colossi were massive creatures created by the Angels and Demons to be their most powerful weapons to use in The End War. These creatures themselves are not living beings, instead being a large construct of Angel or Demon make powered by Anima supplied by either Heaven or Hell. These creatures, once activated, follow the will of the Angels or Demons that created them and will summarily lay waste to any enemy force in its path. Despite this, they are not without their own will and intelligence, and will display signs of high level thought and reasoning, being able to decide for itself the best course of action to take in order to achieve an objective, some being more intelligent than others, with the highest intelligence levels almost approaching actual sentience.
Each Colossus is unique in size and shape, and can range from being humanoid to avian, and can even be geometric. Each Colossus has their own name, and has its own unique set of abilities and strengths that can be used to full effect on the battlefield.
Void Colossi were Colossi that were infected with Void, seen during The First Void Insurrection. It was shown that Colossi infected by Void, whether originally Angel or Demon, possessed much more power than normal. They were also feral and usually ran rampant without any guidance, destroying anything in their way, whether they be Angel, Demon, Human, or other Colossi.