Zoanoids, also known as "Beastialized Soldiers" (in Japanese: 獣化兵), are human beings that have undergone genetic modification to become monstrous creatures designed for combat. In the Guyver series, these living weapons are the soldiers of the Cronos Corporation. They come in many sizes and shapes and possess many different superhuman abilities. Cronos intends to transform the entire human race into Zoanoids, which are all susceptible to the psychic control of the Zoalords.
The actual, exact process that turns an ordinary human being into a Zoanoid is not known; it has been explained as subjecting the DNA of the subject to an array of chemical compounds which cause a rapid reshuffling of the genetic code, 'releasing' information which was already there, but dormant. This is a sort of hit-and-miss process; Commander Guyot quoted that "a good majority" of the subjects die during the procedure. He was not a specialist, however, and given that some people who were processed would be immediately missed if they "disappeared" (Such as White House staff members, or the prime minister of Japan), it must have been possible to ensure the subject would survive. Of course, the intense research performed by Chronos' scientists means things are learned with every processing that is performed, so it may be assumed the survival rate is higher - especially after processing became voluntary, rather than compulsory.
Processing usually takes a day or so on average (Although far briefer, and longer periods are possible); during this time, the subject is suspended inside a tank filled with amniotic and apparently hyperoxidized fluid (meaning, it can be breathed) and hooked up to feeding and monitoring cables. Interestingly, it is possible to prematurely interrupt processing, while the subject still is capable of taking a Zoanoid battle form; however, this will dramatically reduce their lifespan. For instance, when Genzo Makishima was processed into Enzyme-I, he estimated his remaining lifespan at a week, while the Enzyme-II's commander Guyot deployed died within an hour. What type of Zoanoid a subject becomes can apparently be set to an extent; some types are more 'common' in the population, and can easily be mass-produced - examples are Gregole, Vamore, and Ramotith. It is apparently possible to turn any human subject into a Ramotith.
Whether or not a human has been processed can usually be determined through genetic testing, as noticeable changes have occurred in the DNA; some Zoanoid types, however, have a genome so like a human it's indistinguishable from a normal person's.
A Zoanoid battle form is radically different from a human body in many ways, while usually at least semi-humanoid. Many Zoanoids have a forward-leaning posture, with naturally bowed legs and noticeably elongated arms. They have no visible genitals or other gender characteristics, nor, it seems excretory organs. The battle for is entirely geared towards combat, with no regard for other activities, and Zoanoids do not appear to eat. Their physical strength is far superior. While, for instance, Gregole is about eight feet tall and weighs about three hundred pounds, he is fifteen times as strong as the average human being. Muscle and bone structure are far superior to a human's, and the shape of the skeleton is also optimized for strength. In addition to increased strength, many Zoanoids sports armor - either flexible or rigid or varying between the two - their flesh and dermal structure become substantially harder, with durability ranges from simply bulletproof to artillery proof. Some Zoanoids are equipped with weapons beyond strength, claws, and fangs: venom, acid, supercooled nitrogen or even laser weapons. The change is not merely physical: the brain also changes, causing the battle form to also feel like fighting. Zoanoids are all, and always, warriors.
Many Zoanoids resemble existing animals to some extent, usually mammals, birds, reptiles or arthropods. Others, however, appear bizarre and outlandish, with no relation to any known living thing.
When a Zoanoid dies, whether in human or battle form, his body will disintegrate with alarming rapidity; essentially, this is the same process that allows them to transform from one form to another.
Zoanoids that have been optimized for superior physical strength.
Zoanoids armed with organically-grown laser weapons. They are physically weaker than power-type Zoanoids but make up for it with their intense firepower.
Zoanoids optimized for undersea combat.
Weaker Zoanoids that are engineered to possess great speed and agility.
Hyper-Zoanoids are advanced one-of-a-kind zoaforms optimized under the most careful conditions. They possess significantly greater abilities than standard Zoanoids and are even capable of confronting the Guyver on more-or-less equal terms.