↑The Courier: "What are you working on?" Henry: "The Nightkin have varying degrees of mental instability due their addiction to Stealth Boy use. I've been trying to come up with a cure. I'm currently investigating the local Nightstalker population since they seem to have developed a natural stealth field. I've also gotten my hands on a working Stealth Boy Mark II prototype, but that experiment is riskier. I'd rather not pursue that research just yet." (Henry's dialogue)
↑The Courier: "What makes you think that the Nightstalker mutation isn't natural?" Henry: "I've compared the brain chemistry of a Nightkin to one of the local Nightstalkers we killed. They both exhibit similar neurochemical changes. Now, I'm not claiming that Nightstalkers are running around wearing Stealth Boys, mind you. I just don't think it's all a coincidence." (Henry's dialogue)
↑The Courier: "What's wrong with the Nightkin?" Marcus: "Nightkin suffer schizophrenia from the Stealth Boys they're always using. One of the reasons I settled Jacobstown was so they could be cured. While they're in town, the Nightkin aren't allowed to have Stealth Boys so their craziness doesn't get worse. Trouble is the Nightkin don't like being visible, either. They don't take being exposed too well." (Marcus' dialogue)
↑The Courier: "Why are the Nightkin here in Jacobstown?" Keene: "The Stealth Boys we use have cumulative, adverse effects on our minds. Jacobstown was supposed to be a sanctuary, a place to find a cure. Instead, we wait and wait. I'm sick of waiting." The Courier: "Why are the Nightkin here in Jacobstown?" Keene: "The Stealth Boys we use have cumulative, adverse effects on our minds. But, thanks to you, it seems a cure is on the way at last." (Keene's dialogue)
↑Fallout: Wasteland Warfare - Super Mutants: Nightkin: "Creations of the Master, Nightkin are elite Super Mutants. Their purple hue is due to increase experimentation on them, though their name stems from near-constant use and almost addiction to Stealth Boys. This makes them some of the most dangerous variants of Super Mutants, as while they are not quite as strong as standard Super Mutants they are stealthier and have more reasoned approaches to combat – almost verging on tactics."