== Overview ==
Senior game designer Tymon Smektala revealed that in Dying Light 2, they have added the concept of "infected life cycle", which basically adds stages of infection to zombies.
The Viral is an initial state in which the infected is becoming. The Viral is someone who has just been bitten and has just become infected, so they still show traces of humanity, and at this point, they are very fast, very dangerous: they avoid the sun at all costs.
But after a while in that state, they become Biters (Teethers), who are basically regular zombies; slowly infected that, if possible, will try to grab you and infect you or eat you, but the sunlight is dangerous to them, and they are not as fast and agile as the Viral.
The Degenerate is a final stage of 'evolution' for the Viral; Decaying zombies that are very weak with pieces of meat that fall off them. The more sunlight the Biters received, the weaker they will become. In other words, the longer they live with the infection, the weaker they will become, unless they can avoid the sun's UV rays. They really aren't that dangerous for you, but you still have to be alert because Dying Light 2 is a systemic game, many things happen in an emergent way.
The volatile is an alternative route of evolution for those infected. Volatiles are the penultimate stage of evolution in the infected life cycle. Extremely dangerous and agile, it is recommended to sneak around one or more volatile, since alerting one will make them indicate your position to others. Depending on the player's agility tree, you can overcome most of the volatiles in environments with many side streets, alleys, obstacles and traps. However, when it comes to open areas, the Volatile will find it much easier to reach the player. When it comes to weapons to combat highly infected predators, most high-level machetes and shotguns work best to dispatch them in the first game. However, it is not known exactly how different or similar the Volatiles will be in Dying Light 2 compared to the original game.