Clementine and Hinako Shimizu The Walking Dead

The Walking Dead takes place after the onset of a worldwide zombie apocalypse. The zombies, referred to as "walkers", shamble towards living humans and other creatures to eat them. They are attracted to noise and to scents, including the scent of humans.

Dociles:

Dociles, or "Pets", are zombies that have been rendered docile after the removal of their limbs and mechanisms for biting, such as their jaws or teeth. They lose their urge to eat after they no longer have the ability to do so. A person can use them as repellent against other zombies as their smell is masked by the dociles with their behavior modified so they don't attack. Dociles are one of the few variants that are created rather than naturally existing.

Lurkers:

Lurkers enter a state of death-like dormancy until alerted by an external presence in which they attack, entrapping their prey. Lurkers enter this state after a prolonged period of isolation or sustaining an injury that would otherwise be fatal to a living person, mainly to the torso, face, or head. Lurkers are the only type of zombie that appear to have a sleep cycle, as zombies don't require sleep. They are the most common variant form encountered.

Roamers:

Roamers remember aspects of their lives before they died and will roam to find people, places, and/or objects that they recognize. They will return to locations where they previously lived or died, behave differently when encountering familiar people depending on their previous relationship in life, and will interact with objects that once held significance to them. They are one of the few variants that have some level of restraint when alerted to prey.

Climbers:

Climbers have the ability to climb walls and various obstacles, and also can open doors and interact with objects. Due their intelligence, they are capable of problem-solving and self-defense. They are able to use objects as weapons against people, or to destroy obstacles such as glass doors and windows with a blunt instrument. Their strength and problem-solving intelligence makes them among the most dangerous variants. It's possible that climbers are a subcategory of roamers, as they share similar traits and abilities.

Environmentals:

Environmentals are zombies that have been physiologically changed by their environment. They have developed certain aspects and/or defense mechanisms due to their surroundings. Examples include becoming waterlogged, inflamed, calcified, radioactive, bioluminescent; or infested with bees, spiders, fungus, barnacles, hogweed, and other forms of life. It's also possible for other survivors to alter them, such as pouring molten metal on their heads or impaling them with several sharp objects to make it harder for other survivors to neutralize them. Many of these zombies are lurkers due to an inactive nature needed for their environments to alter them.

Vectors:

Vectors, or "Infected", are zombies that carry various pathogens and act as disease vectors to transmit them. Either from dying as a result of the illness, or developing pathogens while as a zombie, they pose a threat by spreading deadly diseases, including novel ones. It's difficult to dispatch or come into contact with them due to the risk of getting exposed. Examples include those carrying the 2012 influenza strain and bubonic plague. According to Civic Republic Military (CRM), all zombies are potential vectors. CRM scientists predict they will contribute to the end of humanity by transmitting diseases naturally carried inside their bodies.

Protectors:

Protectors are alphas of the herd that lead, defend, and provide for them. They are a unique kind of variant as they have problem solving-intelligence, but also alternative behavior that allows them to be nurturing and selfless. At times they will kill their prey and leave it behind for the herd to consume. Due to being at the front of the herd, they use the herd mentality of the zombies to guide them. It's possible that this is a subcategory of a roamer.

Walker Kings:

Walker Kings are a unique variant of multiple zombies fused together, forming a super organism similar to a rat king. It displays exceptional strength and speed by moving at a fast pace, while supporting the weight of additional bodies conjoined to it. Decomposition, fire, and methane exposure are some methods in which the zombies can merge together. Due to is creation, it is a subcategory of environmentals and lurkers. Because of their intricate process, walker kings are the rarest of the variants.

Burners:

Burners, or "Brûlants", are modified zombies that have corrosive acid in their blood. Victims that are bitten, touched, or come into contact with their blood are burned significantly. They are relatively common variants encountered exclusively in France due to their origins as experiments by Doctor Henri LaFleur for the Power of the Living. Cauterization is the best way to treat wounds from them, as it otherwise spreads, and victims can potentially lose limbs as a result.

Notable gangs

The Saviors: A large, oppressive group led by Negan, known for their ruthless control and use of intimidation.

The Whisperers: A dangerous group that wears the skins of walkers to camouflage themselves and blend in with the dead.

The Vatos: A gang from Los Angeles who initially appear hostile but later turn out to be protectors of an elderly community.

The Hilltop: A large, organized community that acts as a major faction in the series.

Terminus: A group of cannibals who claim to be survivors but are actually a trap for other survivors.

The Detroit Gang: A group that was present in the city of Detroit.Los Hermanos: A drug cartel that appears in Fear the Walking Dead.

La Mañas: A highway gang known for being feared in the area where they operate.

Rick's Group: While not a gang, Rick's group is the central "gang" or survivor community in the original series.