Enchanted Realms Rulebook
Altering Perceptions
Certain spells, abilities and items can create illusions. There are basically three subtypes of illusion. It is important to understand what each is because how these affect their victims are different with different immunities. Also note that charming, while magical, is not an illusion. Some illusions may affect the mind in a way that seems like a charm; however, these are too different types of magic.
The three subtypes of illusions are glamours, phantasms and shrouds. All verbiage in the printed material are very specific in usage to ensure what kind of illusion is in being applied.
Glamours
Glamour illusions create actual images, sounds and smells. Think of this magical stimulus as holograms where all observers respond to the perception. However, senses to perceive the illusion is required. Thus, non-ocular undead, such as skeletons, would not be affected by a visual glamour; however, a vampire, which does have normal vision, would be able to see, and potentially be fooled by a glamour. For a nearly mindless creatures, like a Mind-Zero animal, any save would automatically fail against a visual glamour, whereby the creature would react according to its nature.
Phantasms
Phantasms are illusions in the psyche of the victim. They are merely perception, albeit often powerful one. Nonetheless, only the minds affected can “see” or “hear” the illusion. Others may wonder why their ally is wrestling “nothing” on the ground. Mindless undead, plant-monsters, and other creatures who are not affected by mind-altering magic are immune from these types of illusions. Further, if someone has dark mind or other mind-shielding, phantasms may not be able to affect him or her.
Shrouds
Shrouds are illusions that alters, conceals or modifies the perceivable messages of an object. This is similar to a glamour illusion in that the image or sound is real, observable to anyone able to sense it. However, it alters and masks the light, sounds, smells or tactile information. In some cases, such as veil, it conceals the information. In other cases, shrouds alter the imagery. Those of lesser intellect would react to shrouds the same way as a glamour, even in the face of things that would defy logic to a thinking being. Where a person bumping into an invisible object would deduce something is there, the mindless strix would not realize there was anything beyond its sensory perception.
Even when an illusion is known to be false, what persists depends on its subtype. Nothing in the environment changes for glamour illusions and shrouds. The deception may be known, but the “hologram” or background-noise would still be seen and heard. However, once discovering that a phantasm is only an illusion, the perception will vanish. However, a GM might find it fun to take some psychological parting shots as the nightmare fades away over six or seven seconds for story-telling value.