An egregore is a tulpa created from the collective psychic power of a noosphere, spontaneously manifesting during extremely rare moments where a noosphere's thought is focused on a single concept. Created egregores typically die shortly, a rare few having an intelligence developed enough to maintain a form- whether it be as a flux construct or by parasitizing from individual minds or crowds through neuroinvasion abilities, or some other form altogether such as a real body created using powerful metacreation abilities.
Egregores make up a portion of so-called "hyperspace entities", and have varying personalities and motives depending on the circumstances of their creation. An egregore created from a noosphere's suffering during a large-scale war may embody relevant qualities of war, for example.
The power of egregores can vary, depending on the circumstances of their creation; stronger egregores are created from a stronger unified thought held by a noosphere. An egregore created from something like a famine may be weaker than the egregore that was created during the events of Earthfall, for example. Once created, an egregore is an individual entity with its own free will separate from the whims of the noosphere.