(Capcom's primary storyline)
The Afflicted are humans exposed to the t-Phobos virus; torture and abuse triggered fear within their bodies causing them to mutate and act violently towards non-infected people. The afflicted are initially found in an abandoned prison complex which belonged to the former Soviet Union. A few of them are also found in the town, suggesting that the remaining inhabitants of the island were also taken to be tortured and experimented on with the virus and then escaped confinement and started wandering around the town and the sewers.
The subjects had no eye contact with the daylight; being closed in those dark cells for years caused them to become mentally unstable and make their vision weak. This is the reason why they are vulnerable to light and can easily be stunned by a flashlight.
As said before, the virus that creates the Afflicted is triggered by fear. When a victim reaches a certain level of anxiety and fear, they mutate into an Afflicted within seconds. The victims also seem to lose their sense of fear afterwards, feeling a mix of euphoria and fatalism. The first such mutation seen was that of Pedro Fernandez.
A few Afflicted had large tumors on their heads, this being a side-effect of the virus.
The Afflicted were humans in origin. Their bodies and minds were heavily altered because of the virus and their terror they underwent, by torture and other kinds of abuse. Their skin is yellowed, darkened, and covered in open wounds. Evidence of the torture they endured still present, such as barbed wire tightly holding on to their flesh and sharpened pieces of bar pipes impaled through their bodies. Driven completely mad from the pain, solitude and fear, they react to any living person in sight with immediate violence. Through means of scratching, biting, or even using rudimentary weapons, they will do whatever they can to kill whoever they find in the areas of the prison.
Being human, they still at least hold some degree of intelligence comparable to the C-Virus Zombies of Resident Evil 6, able to use weapons and climb ladders to pursue potential victims. They present a vulnerability to light, easily blinded and stunned from being flashed directly in the face with a flashlight.
The Sploder is a mutated version of the Afflicted, that has developed red pustule-like organs inside their bodies which will explode while being near to their target. Some Afflicted sport large crimson pustules on their faces. Though no different in nature to ordinary Afflicted, these Afflicted will create Cysts if killed by a headshot and the resultant "red pus splatters" can be dissolved with Moira's flashlight.
Due to the Afflicted being extremely violent, they will attack the player on sight, attempting to scratch or attack the player with any weapons they might be holding. If an Afflicted gets an opportunity to grab the player, they will proceed to bite them until they get shaken off. The Afflicted will even rush and leap at a player to attack mid-air with whatever they have on-hand.
Even simple handguns like the HG-MPM have stopping power against an Afflicted, with single shots to the legs or body capable of slowing them and shots to the head even able to stun them for a follow-up physical attack. Damage to their face and head is extremely effective with firearms. Players using Moira are also able to utilize the Flashlight to stun Afflicted by focusing the beam on to them. Using stealth against Afflicted is also a viable tactic, especially with Moira who is able to use her Crowbar to incapacitate an Afflicted that is attacked from behind. The crowbar is also an excellent follow-up to preserve Claire's ammo, as it is capable of performing a finishing blow on an Afflicted that has been grounded.