Regular Zombies: Zombies, normally mindless, are able to regain some semblance of their former selves upon consumption of an Human. Although most Zombies cannot talk, most are incapable of forming complex thoughts, and some are little more than beasts. Most Zombies have no memories of their former lives, so finding a Zombie with intact memories is the rarest of miracles.
Alpha Zombies: Alpha Zombies are smarter variants of the more common Zombies, capable of organizing into a form of society. They're self aware and capable of forming relationships, and more aware of their surroundings, enabling them to dodge attacks and engage in other decisive actions. They are stronger, smarter, and can have intelligence to that of the smartest animal in which cases rivals that of humans. A person who is bitten by Patient Zero(MC) will become an Alpha, but the virus varies differently in people.
Patient Zero (MC): The progenitor of the Zombie virus as he was experimented within a government facility and became the first Zombie making him an Omega Zombie and the only one of his kind. He's retained most of his humanity making him alongside a few of his Alphas unique among other zombies. Most if not all Zombies see him as their King as his sires(Alpha Zombies) other than himself are the strongest, fastest, and smartest zombies to exist as they are extremely loyal to him. He and his Alphas will not rot away like other zombies as they are basically immortal. When he bites ordinary people, they turn into Alpha Zombies and if their will is strong enough, they can retain most of their humanity. If not, although they are still smarter than regular zombies, they are as smart as an intelligent animal but not as strong as an Alpha whose retained most of their humanity.
Volatile: Volatile is an infected that only emerges during at night. They are broad-shouldered and slightly taller than the average Zombie. Other physical markers include full-bodied nudity, exposed bone and muscle and a mandible jaw that it uses against non-infected humans. They can audibly be identified by their heavy breathing and loud screeches. Volatiles are extremely fast, and can navigate through the dark at high speeds abit slower than an Alpha.
[AN: Will add more as the story goes on]