Virals are humans that have only very recently succumbed to the infection. However, they are still physically alive as they are seen speaking multiple times. As a result, their bodies still retain the physical strength needed for them to possess a high level of fitness and agility. They run far faster than any other Infected, except for the Volatile and Night Walker. They can also jump and climb over obstacles and buildings, allowing them to chase after the player even when he's in a spot where most normal infected can't reach.
Unlike the slower, lumbering types of infected (that all virals will eventually reach as their bodies degrade), Virals do not bite, nor could they 'lunge' at a player and trap them into a QTE; instead, they use their hands to viciously claw and punch their victims.
Virals possess advanced mental faculties when compared to their Biter counterparts. They often dodge attacks and hang back from the player charging in and backing off.
As of the Enhanced Edition update, they also posses new behaviors that allow them to get the jump on players and further enhancing their combat abilities. One of the most dangerous new parts of their behaviour is the tendency of then to shuffle about in crowds of biters and appear fully normal. Once an infected in the crowd is attacked, they will release a small cry that will trigger all virals nearby. This will not spawn new virals, it will only attract ones that are already nearby and are in "Shuffler mode". After becoming triggered, virals will function as normal, (pursuing the player, climbing, and killing as normal) as well as constantly screaming as the player fights or runs to trigger other nearby virals (note this does not spawn new virals either). Viral combat behaviour is now dynamic based on the composition of nearby infected. When alone, they will behave suicidally and is more likely to be for its life, attacking viscously they do as much damage as quickly as possible. When near biters, they will wait until the biters have swarmed the player, hanging to the back where they can not be damaged, and will charge in briefly before retreating quickly and getting behind the player again. When multiple virals or a Goon is present, they will do the same behaviour as they do when Biters are present except the virals will work as a team and charge in one at a time from multiple directions, surrounding the player, and will come in one at a time in a random order. When other specials such as a demolisher, volatiles, toads, or bombers have aggro on the player, the Viral will attempt to prevent the player from moving by getting in the way and surrounding the player
In The Following expansion, there's a new variant of Virals. Known by players as "Viral thugs", these virals are taller than their counterparts and emit low pitched monstrous screams. What makes these virals unique is that they have the ability to knock over the player with every single successful attack. These virals posses similar traits to the thug enemy from the Dead Island series as they both share powerful strength to knock over a player, hence why they're dubbed as "Viral thugs". These type of Virals can be found naturally around the countryside or if you encounter a "Biter thug" undergoing nightmare or day-mare effects. It's best to eliminate Viral thugs quickly, for as they can delay your attacks constantly if you don't strike them in time. The original source of mutation may be due to the abundant amount of chemical activity in the countryside or by the vastness of the countryside, causing the virus to adapt to the environment.
Virals are attracted to four types of sounds:
- Gunshots: Depending on the weapon, it usually takes at least three to four consecutive shots for a pistol and rifle, and two to three shots for a shotgun in order to attract Virals. Weapons fired by Rais' men will also attract Virals.
- Explosions: These can be caused by propane tanks and/or fuel barrels that have been ruptured and exploded. Grenades tossed by the player will also immediately attract Virals, as well as Gas Tank's oxygen tank when exploded. However, Kurt's Bombs, the poison variant of the grenade, Air Strike, and Trap Bombs, while explosive, do not attract Virals.
- Structural Breakage: This can only be caused when the player lands on a flimsy roof from a high enough distance, breaking it as a result. The player can also break a roof by shooting it or hitting it with a melee weapon. The sound of the roof collapsing will always attract Virals.
- Screamer: Cries will also draw a nearby Viral and spawn new ones. Silencing screamers is a priority as they will infinitely spawn virals while they cry.
- Dead Biters: If you get close enough to a dead biter, its head will explode giving you light poison and they will come towards you in seconds
Additionally, Virals are automatically triggered to go after the player randomly at a certain point in the game, or on higher levels there is a timer which when it stops it triggers Virals after you.
- It is generally best to vacate an area if too much noise is made and the sound of Virals are heard. If it is not possible to flee, using camouflage can help the player to evade them.
- Grapple is a very useful skill when fighting virals on even ground. You can use it when a viral lunges towards you to avoid its attack while throwing it off-balance at the same time, allowing you to get easy hits on it. A Brutal Grapple and Stomp combo is even better, allowing you to kill a viral instantly. Grapple can also be used when on high ground to easily throw a viral off a building, which can instantly kill them if the building is around three or more stories tall (sort of uncommon in the Slums, but very much omnipresent in Old Town).
- Even if you cause an explosion far away, be aware that virals will turn towards you, regardless of whether you were the source of the explosion or not. This is important to remember when trying to use gas bottles as distractions. Throw a lit gas bottle from the top of 5—10 story building into a courtyard of zombies, the virals will still climb all the way up to kill you.
- Virals will often stop to scream at a player before engaging, and while doing this they wont attempt to dodge any attacks. This is a good opportunity to knock down, or outright kill one before it can throw a single punch.
- Using guns on Virals is not recommended, as they can be hard to hit, and the noise will only make your problems worse, by attracting more Virals and wasting ammo.Though it takes 3 consecutive shots to attract Virals so try to be accurate and allow at least 5—7 seconds between shots.
- The player can evade their pursuit by breaking line of sight and staying quiet. If a tall, vertical structure is available, such as a telephone pole, the player can climb up high enough so stay out of reach of the Virals. Unlike Volatiles, Virals cannot spit at a player they can't reach, and will eventually grow bored and leave.
- Heavy, slow weapons that take a large amount of time to swing and recover — especially something like a two-handed hammer or a baseball bat — are not recommended. Virals are extremely agile and move erratically, meaning that they can easily avoid a swing and get in for a counterattack while the player is still trying to recover from the inital swing. Light, fast weapons, such as a knife or one-handed melee weapon, are more suitable against Virals.
- The Leg Breaker move will instantly kill them, but can be tricky to pull off as they will try to dodge it. It's recommended that the player try to stun the viral via another ability first if you try to pull this off.
- As Virals climb onto a ledge, they are vulnerable to the finish move, which will kill them instantly if kicked.
- When frozen by Freezing Throwing Stars, they can still dodge melee swings.
- Virals are vulnerable to fall damage. Knocking one off a high enough roof will kill it. This can easily be done by using the counter move and throwing it off a ledge when it attacks. The same move can be used to toss one into spikes, killing it instantly.
- The Stomp skill still prove very, very useful skill against Virals. Once the skill is unlocked, whenever Crane hears Virals, he can run to the nearest high ground, such as Vans, and take out every single Viral while they're climbing up, which is when they're most vulnerable. It's also possible to kick Virals, instantly causing them to lose balance and fall down to the ground while they're still in climbing process, giving Crane enough time to recover the lost stamina. If any Viral successfully manages to climb up the ground Crane is standing, Crane can proceed by either using Tackle or jumping down, luring Virals to also jump down from the high ground, such as Van, after that Crane can return to the same high ground and repeat the same strategy.
- After unlocking the Grappling Hook, it'll become much easier to evade unwanted combat with Virals.
- Because Virals have recently turned, they still retain some bit of humanity in them. When the player attacks a viral, male or female, they will sometimes stop attacking, cover their head with their arms, and beg for their lives. This lasts only for a brief second, as the virus regains control of its host's neurological system and the Viral turns again.
- This means when they become a Infected, then they are pronounced undead.
- Virals are a homage to the Infected variant of zombies from Techland's Dead Island, which are themselves homages to the Infected from the British 2002 film 28 Days Later.
- Virals tend to appear suddenly, either bursting through doors, crawling from under cars or popping out of sewer manhole covers. There also seems to be a large number of Virals and Volatiles in the sewer system.
- Virals can be taken down fairly quickly with body shots when it comes to firearms, however there are some drawbacks — trying to shoot at Virals will create more noise and lure even more Virals to the player's area. Virals also move very quickly and unpredictably, making body shots very hard to land, much less headshots.
- Virals can very rarely survive having an arm or hand severed, but not a leg or foot.
- When severing an arm, the Viral will have a death animation of it grabbing its stumped arm while bleeding out before falling down and dying. However, the animation can still occur when the Viral is both decapitated and lost the arm. This looks very irrational for it to occur and impossible with the brain being disconnected. This may possibly be an oversight from the developers. However, given that the infection is caused by an intensely mutative and genetically-altering super virus, this occurrence is not too far-fetched in theory.
- Virals run at around the same speed as the player on a straight-away.
- In some areas, Virals are prone to spawning one after another, notably in or around mission objectives. This can make searching for an objective difficult as a stream of the infected constantly swarm and attack the player.
- Virals seem to spawn more often at Old Town.
- Virals are the day-time equivalent of Night Walkers and vice versa.
- Albeit during the day, Virals don't have a cone of vision on the map like the Night Walkers and Volatiles do at night.
- Virals can still be present after sunset providing that they have been there during the daytime/leading up to nightfall albeit once the player goes away from them/causes the game to despawn them, they will be replaced by Night Walkers.
- Also, the same Virals won't have a visible cone of their vision on the map after sunset unlike the Volatiles and Night Walkers.