Error is the term for those who were never meant to exist and do so freely, unbound by the Script of Creation. They are a sad group of individuals unaware of their inevitable fate to be erased to correct the Script or to clash against the Weavers in an ultimate battle that will determine the fate of Creation itself.
The number and exact members of Errors are indeterminable. Several have been eliminated over the course of Time.
The Symbiont is a Weaver. However, its fiddling with Errors on the doomed planet of Pangaea created the collective of Errors called The Thirteen. It itself has merged with one of these Thirteen, giving it the alternate name of Alandau.
The eldest child of the Ancient Hallowe'en and Nigh Mähre, Hobboilen is the eldest canonical Error (not including the Symbiont). It is a true neutral evil entity that is so powerful, even Weavers are wary of dealing with it. Its mate is named Dthanthomien.
The youngest son of the Faifethi Ruqaiyah and Indrahti Nahuel is a hybrid of two incompatible species. Hailing from Rejisea, he is also the second youngest Error, powerful enough that he is called a "Little God" despite his inability to create.
Some Weavers have gone on to say that Time itself is an Error, as it cannot be controlled by the Weavers as freely as they should have the ability to. It is a canon element, as all the Weavers came together to invent it, which would instead make it a Misconstrue, not an Error.
Time itself is a semi-sentient element of Creation.