Gnomes (also called Guardians) are mysterious guards that patrol the forests around Tower Prep . They usually stay hidden in the forest, although they also secretly enter the school buildings through underground tunnels, which may be their base or resting place.
Gnomes have always seemed to be around, and may be tied to the beginnings of the school. They are feared by the other students, who have given them the name "gnomes," because they fear to think what they really are. However, they refer to themselves as "guardians," a name also used by Headmaster .
Gnomes wear black body armor with spikes protruding from it. They have two eye-like lights mounted on their helmets; most have green lights, but there is at least one red-eye gnome, suggesting each one with the red lights is the leader of each group of gnomes. They make electronic noises, which are apparently encoded voice communications between gnomes.
Gnomes prefer to stalk their prey and then engage in hand-to-hand combat. They have the ability to emit a loud noise that causes discomfort to humans. It is similar to the noise students hear before they are abducted after they were listening to something made by SatoSystems.
Gnomes are apparently used as guards to keep students out of the Forbidden Zone. They will chase and engage in combat with people although it's not clear whether they turn the students they capture into gnomes, or simply detain them and send them to West Campus. It appears that Headmaster has direct control over them.