Zombies are really less a liminal race than a condition, as they are in actuality deceased humans brought back to life thanks to a special infectious disease, and as such, are totally dead in the biological sense but still possess enough brain activity to continue function as though they were biologically alive.
- Due to being biologically dead, a Zombie's body is vulnerable to the same manner of decay a normal corpse would exhibit, and unless prosthetic intervention is taken, their bodies will presumably rot past the point of functioning.
- Said prosthetic intervention can be in the form of being doused in preservative chemicals or receiving artificial organs.
- Some Zombies may also graft replacement parts to themselves. As they do not heal from wounds, the practice of "limb replacement" also serves as a manner of repair. Whether there is a restriction on what they may graft onto themselves or if they are indeed able to graft any sort of thing anywhere on their body is unknown.
- The brain is assumed to be responsible for a Zombie's body functioning, and physical connection to it in some way is necessary for the Zombie to become animate. While at least moderate damage to the brain has not shown to have any negative effects on the Zombie in question, whether a body would continue without its brain is currently unknown.
- Due to them being dead, Zombies have high pain tolerances and non-weapon-based damage thresholds, though this doesn't dampen their ability to feel pleasure.
- A zombie's blood is composed of a toxic batch of preservation fluids made to be blood-like.
Early Zombies (アーリーゾンビ, Ārī Zonbi) are zombies created before the establishment of preservation technology. To prevent further decay, they spend most of their time in refrigerated rooms. They are only able to go outside during cold winter periods. Because of their incomplete preservation, their brains are not entirely intact, making them very easygoing with energy levels of a person who has just woken up.
Mummys (ミイラ, Mīra) are a zombie subspecies from dry desert areas. Their arid environment keeps them safe from decay, and even without preservative measures, their bodies remain intact. However, their arid environment has also robbed their skin of its moisture, requiring them to take long baths to replenish their fluids. They also supplement this by sucking the life force out of young men to preserve their beauty, but this tragically functions only as a placebo.
Since many Mummies were ancient royalty or nobility in life, they often have difficult personalities.
Jiang Shi (キョンシー, Kyonshī, original Chinese: 殭屍 [Traditional]/ 僵尸 [Simplified], lit. "Stiff Corpse" in Chinese), known also as "Chinese Hopping Vampires", are a zombie subspecies found primarily in Asian countries, such as China and Taiwan.
Unlike standard zombies, hopping vampires are severely affected by the symptoms of rigor mortis, making their joints, especially their elbows and knees, particularly stiff. Because of this, they must practice tai chi every morning to stretch. However, their joints always stiffen to some degree while they sleep, forcing them to hop around with their elbows and knees locked straight out.
A Frankenstein's Monster is a subspecies of Zombie that has been "created" or "born" through the combination of compatible organic parts to form a sentient, functional being.
While similar in nature to, and sharing many attributes with the Zombie species, Frankenstein's Monsters differ in how they are created; while Zombies were once living beings, Frankenstein's Monsters were created from "birth" as true undead beings.
- Yuhi (Converted; originally human)
- Fran (Frankenstein's Monster)
- Cici (Jiang Shi)
- Kyou (Jiang Shi)
- Mokunaii the 11th (Mummy)
- So far, Zombies are the only monsters in the series that are stated that they were once humans in a previous life.
- Mummies being former royals and using the life force of their victims for using it for maintaining cosmetic appeal may be in reference to Elizabeth Báthory, who was infamous for bathing in the blood of her victims in an effort to maintain her youth.