Zoanoids are the lowest-ranked and least powerful of the Zoaforms created by the Chronos Corporation in Guyver. They are usually used as cannon-fodder in the various battles that Chronos engages in during the course of the series.
Zoanoids in canon
As the series itself begins in Japan, and is set there for the most part, the Zoanoids most frequently seen are those of Chronos' Japanese branch. Gregole is the first complete Zoanoid glimpsed in-series, coming just a few chapters after the reader/viewer is introduced to the desperate, dying, unfinished Zoanoid Malmot.
Not long after he appears, a troop of men in variously black or blue bodysuits show up in pursuit. These are Chronos' troops: men who have been processed into various breeds of Zoanoid, to be sent on various missions for the company. Typically brash and supremely confident in their abilities, Chronos' front-line troops are not often mentally prepared when they confront something that they for all their power, are unable to deal with.
As such, they often come off as disposable cannon-fodder, an appearance that seems to be quite close to the truth.
As front-line soldiers in Chronos, they are often the first to confront the various threats presented to the company, which considering the scale of said threats means that they often die in droves.
Some of the more common breeds of Zoanoid are the strength-type Gregole, the scout-type Razell, and the fast-moving Malcult. The bio-blaster Vamore is a rather new type of Zoanoid, rather weak compared to its brethren, but with bio-lasers that can penetrate up to 30 centimeters of concrete to compensate for its relative physical weakness.