Night Walkers are extremely fast and agile, and behave very similar to a Viral. They can easily be identified from the misty substance that they emit (both during the day and at night). During the day (apart from in The Following), Night Walkers often cower from the sunlight and are usually not a threat.
During the night, however, Night Walkers are far more dangerous. While they are still significantly weaker than Volatiles, Night Walkers are still stronger and faster than the daytime Viral. More importantly, they are able to detect the player and initiate a pursuit. As a result, Night Walkers usually serve as scouts, drawing the attention of the horde and the far more dangerous Volatiles upon spotting Crane.
While Night Walkers share similiar behavior to Virals, they are faster and far more aggressive. They never attempt to dodge or backstep Crane's attacks like a Viral would, instead opting to charge in and do as much damage as possible. Unlike Volatiles, they cannot pounce the player.
Biters will transform into Night Walkers under a few conditions:
- During a pursuit, when Kyle runs near any number of Biters. The higher the level of the pursuit, the more Biters will transform to join in the chase. This is the most common source of Night Walkers.
- Any kind of loud sound (gunshots, explosions, breaking roofs). Some "quieter" sounds that will not normally draw the attention of a daytime Viral can ocassionally trigger transformations as well, such as the sound of a Goon's rebar hitting the ground.
- When a Biter starts taking a lot of damage in the presence of other Biters. This will usually happen when nearby Biters start to roar (which will also draw the interest of any Volatile within earshot); it is unclear if the transformation is triggered by the roaring itself, or as a defensive response to the Infected sustaining damage.
Although easy to fight in small numbers, Night Walkers can easily build up to dangerous numbers, and do the most damage when the player is distracted trying to evade or fight a Volatile. Because they can transform rather spontaneously, especially during a pursuit, they make navigating Harran at nighttime more risky, and trying to esape or hide from an ongoing pursuit even harder.
- A Biter will take a few seconds to transform into a Night Walker, and the animation and noises it makes during the transformation will be fairly obvious. Take advantage of this delay by running out of its vision range (assuming you are undetected), or killing it before the transformation can complete.
- Night Walkers are vulnerable to UV light just like Volatiles are, and will stop running to shield their eyes. Shine your UV flashlight and use flares to buy yourself more time and distance during a chase.
- Like Volatiles (and unlike Virals), Night Walkers run faster than Kyle and will catch up to him on a straight path, unless he is using a speed potion. Climb, slide, jump over obstacles, and make sharp turns to distance yourself.
- When being pursued, try to avoid large groups of Biters. As long as the player is being chased and Biters are near, it is guaranteed that enough will transform into Night Walkers to make escape even more problematic for the player.
- Killing a Night Walker with the Takedown ability will not alert the rest of the horde.
- During the final mission of the main story, biters can be seen turning into Night Walkers during the day, which is a rare occasion.
- The infected that attacked Kyle Crane in the game's introductory cutscene appear to be Night Walkers, given the fact that they look like Biters but run like a Viral. Although Biters can transform into Night Walkers in the Following, no Night Walkers are seen during the daytime in the Slums in-game.
- Unlike the Volatiles that run back to Dark Areas at 06:00, instead the Night Walkers will transform back into normal Biters or sometimes shield their eyes from the sunlight, meaning players can take advantage and easily kill the blinded Night Walker.