When something in our universe gains sentience, it creates a breach between itself and the other two dimensions, Nihil and Vitae. When this creature endures strong emotions, pain or feelings, the breach widens, and energy from one or both of the dimensions can flow through, called Ignum.

Nihil and Vitae are opposites, with (metaphorically) Nihil being a dimension full of darkness, evil and hatred, and Vitae full of light, hope and joy.
<Neither of this is confirmed, though it is effectively considered common knowledge>

Both dimensions are physical, though any matter that comes into contact with the ignum inside these dimensions causes instantaneous annihilation. Any energy released by this reaction has of yet been undetectable, and unrecoverable.

<Both Nihil and Vitae are an approximated 5x smaller than regular reality, allowing Warpers to allow for rapid transportation.>

When a person endures enough emotion to completely break, they may widen the Ignum breach far enough for an Aberration or Celestial to come out.

Aberrations are the "creatures" from Nihil, resembling those from many folklore, with grotesque fleshy forms, dark shadowy tendrils, or in some accounts feathers and oddly shaped limbs.
They often show in forms that the person it comes from would find 'horrifying', and in some cases will struggle to form at all if the person cannot feel fear.

They will attempt to murder, consume or destroy everything nearby, and will not stop until destroyed, or otherwise killed.

Celestials are the "creatures" from Vitae, often resembling biblically accurate angels, with hundreds of eyes, spinning wheels, wings, white flames and golden halos.

They will attempt to reach any sentient creature nearby, before telepathically (within a few hundred meters) placing an intensely powerful cognitohazard into their mind, placing them into an eternal state of comatose. it is believed they do this in attempt to save them from pain and negative emotion.
<Attempts at reverse engineering the cognitohazards via brainscans have been attempted, with blurry images of forests and natural biomes being produced, which themselves give no side effects.>

Celestials will return to Vitae after a set amount of time without finding any sentient creatures, with the lowest recorded being 11 hours, and the highest being three years. it is unclear if any Celestials have ever been destroyed, or harmed.