This is an in-universe comprehensive overview of Humans, Super Mutants, Ghouls, and other Man-made Sapients, made by a Nightkin scholar named Zekhau, who features in our Fallout: Caldera faction The Firemen.
I've included little citations to certain concepts, though this also contains quite a bit of speculative lore-welding - including everything from the original Vault 13 GURPS timeline to the apocrypha of the Fallout Bible - as well as references to our unreleased Fallout Rewrite.
Below the cut is a full excerpt as a preview!
Misconceptions On Nightkin
To be Nightkin is to reject the harsh light of the great flame and to become kin with the night, for in its darkness all are equal. Such is the name we choose for ourselves, still reverent to our Night God even as we unlearn or reject his tenants - in fact, it was once that all Metamorphs were Nightkin, until age and changing tongue saw the shift. Now only those who pledged themselves the deepest are still referred to as such - telltale in our strange skin and manner.
Many misconceptions reside on both - but in truth the explanations are some simple and some complex.
To the nature of our skin, it is a simple mutation: In all strains of Metamorph, a curious development of yellow-pigment in place of our melanin as brought about by FEV - but so too is another, which causes blue or purple tones, those typical in the ‘Born’ Igneous. It is the loss of the former which causes our cerulean parlor - the Old World termed such ‘Axanthism’, that which prevents yellow in many green Amphibians thus turning them to blue.
This seems to be an effect of our use of Stealth Boys - to which many ascribe the changes in our minds as well. The latter is… not an untruth, but not correct either. In all natures of the mind, the answer is more complex.
It is true that the Stealth Boy, prolonged of use, causes paranoia, delusions, a creeping organic psychosis which makes the world fuzzy and strange - the inner circle of the Brothers of Steel have reported as much, so say the watchers. Yet this is so often confused, conflated with the Pre War term ‘Schizophrenia’, a diversity of neurology with many stigmas even then, whose presentation is not always the similar - more often catatonia in nature, or flat in emotion, chaotic of speech or sense.
Similar, but distinct - for while this can be supported by community or aided with Chems known Antipsychotics, the usage of a Stealth Boy deteriorates the physicality of the brain itself, requiring other methods of assistance. Even so, this does not elaborate the reason why even without, so many Nightkin are strange in compatriots eyes.
Nightkin were the best and brightest of the Master’s Unity, and as such were given the hardest tasks - those of bloodshed and subterfuge, of hearing the First Hive most clearly, to which the loss of such we know was devastating. This reveals another secret: that of remembrance - where as others change upon transformation begat a forgetting, many of us recalled old harms, of overseers and vaults and pain of wasteland or fear of being taken to the Unity.
For some, we were always this way, and our diversity of mind made pain and change natural to us. For those who were many living as one, their mind-kin stepped forward to take the pain. For those who survived pain, we embraced it.
For some, when the Master fell, we embraced Stealth Boys, becoming one with the Night in the only fashion left to us. In the absence of Hive, we listen to whatever voices we can - and in the absence of even that, our minds invent ones to hear.
For some seeking stability the answer may lie in Nullification of noise, Amplification of voice, or in medicines strange. For others, simply others familiar may be our savior. I myself have found kin in strangers, born not from Unity but from Spore, and in those that read my scriptures.
Should you require it, seek out the strange - kin in mind can work as one, should we have kin in heart to guide us.