Nightwalkers, also referred to as Nightless, are a mysterious race in Guilty Gear series. They are very similar to vampires, although seemingly without their traditional weaknesses. Thus far, only two Nightwalkers are known to exist: Slayer and Nagoriyuki.
Nightwalkers are physically indistinguishable from humans, simply having lengthened canines as their one unique trait. Otherwise, the two known vampires in the series have little in common, though in Nagoriyuki's case, he may display blood-red eyes and black sclera from time to time due to the so-called "blood rage".
Little is known about the history of Nightwalkers, much less their origins. At some point in the distant past, the Nightwalkers were enemies of the entire human race; however, all but a few were destroyed. Two such survivors were Slayer and Nagoriyuki. It is also suggested that Nagoriyuki's master, Kazusanosuke, is also a Nightwalker.
Though little is known about their baseline abilities, Nightwalkers are believed to have several the usual defining traits of a traditional vampire. They possess immortality, a thirst for blood, and are physically superior to human beings, being famous for their amazing regenerative abilities. and their blood manipulation abilities. They are able to regenerate normally fatal injuries, including lost limbs, almost instantaneously, with Slayer showing the ability to control his own arm after being cut off.
Having a genetic structure entirely different from that of a human, it would appears that Nightwalkers can turn humans into vampires by the process of drinking their blood. As for the classical weaknesses of vampires (sunlight, silver, garlic, crosses, salt, etc.), they seemingly do not apply to Nightwalkers—at least, in any meaningful way—, as they are shown to withstand sunlight with no apparent issues. However, during Johnny's Treasure Hunt, Slayer's precious item is sunscreen with a sun protection factor of 200 (for comparison, the highest that humans use if SPF 100), hinting at how he is able to minimize the effects of sunlight.
- When defeated in combat, both Slayer and Nagoriyuki recline casually on the ground, almost as if bored, showing them to be in a power-tier all their own above the rest of the cast.