Nightkin

The Nightkin were an elite warrior caste in the Master's super mutant army. They can be found in the upper levels Cathedral, as well as inside the Mariposa Military Base and the nearby cells surrounding it in the form of random patrol encounters. They were superior to other supermutants in skill, equipment and weaponry. The Nightkin were all equipped with cloaking devices, the Stealth Boys. The only gaming effect of this is to give them a slight ethereal look, as it does not affect the PC's chance of hitting them.

After the Master's fall, many super mutants become a chaotic wasteland wandering force, which destroyed everything it encounters. During the time of Fallout 2, some of the super mutant gangs include the former (or so called) nightkins, who, however, don't use Stealth Boy anymore.

A part of super mutant army remained together after the death of Master. This faction was led by Attis and, many years later, captured the Secret Vault in order to use FEV stored in it. Attis's goal was to continue the Master's plan. His army had an elite unit of Nightkins, however, they were much improved and used some new, high-tec suits to advance their abilities. These suits probably originated and were made from Vault-Tec facilities in the region.

Appearances
The Nightkin appeared in the first Fallout game in the Cathedral and Mariposa Military Base. They also appear in Fallout: Brotherhood of Steel. The Nightkin also appeared in Fallout 2 as a hostile encounter on the World map. The mutant commando advanced character class in the cancelled Fallout d20 was based on the Nightkin.