In this article "illusionist" means anyone who creates and controls illusions. This individual does not have to be a member of the illusionist class. Magic-users may choose Phantasmal Force as a third-level spell, master thieves may cast illusions from scrolls, and some monsters and magical items may create illusions.
The image: mental or physical?
A visual illusion is an image without substance. It cannot affect
objects or creatures that do not perceive the image. But is the image
itself real? Does it reflect and absorb light as a photograph or
painting would, or does it exist only in the minds of its victims?
Official publications give no explicit answer, but there are two reasons
to believe that illusions are as visible to the eye as to the mind.
First, if illusions directly affect the mind of the viewer, then they
should be blocked by techniques which protect the mind. However, no
mental defences are effective against illusions. As examples the
psionic discipline Mind Bar and the spell Serten's Spell
Immunity are each effective against many mental invasions, yet
neither is described as defending against illusions. Thus illusions are
unlike mental attacks.
Second, projecting illusory images into viewers' minds seems
unreasonably powerful. According to the Players Handbook, page
75, "all believing creatures which view the Phantasmal Force" are
affected by it. The viewers can be at any distance, and need not be
known to the illusionist. To affect all viewers' minds directly
requires magic to reach over tremendous range and area, and into an
unlimited number of minds (consider the illusion of a flying dragon
viewed from miles away by a large army). Further, each viewer's image
must be different to account for distance and viewing angle. This
unique perspective must be handled automatically by the spell because
the illusionist might not know where all the viewers are. If that's how
it works then Phantasmal Force and its kin are powerful spells
indeed!
Illusions seem more reasonable if they work like mobile,
three-dimensional paintings. Painting with magic, the illusionist
creates an image which is seen by the viewer's eyes. The magic is
restricted in range and area of effect. The illusionist need not locate
all the viewers; anyone who looks at the illusion will see the image
with the correct perspective.
If the image is real, then the image should be visible even when viewers
know that it is an illusion. In that case, illusions could be used for
special visual effects, such as obscuring a view or providing light.
This encourages creative, non-violent uses of illusionist magic, which
is another good reason to choose the "real image" interpretation.
In the rest of this article, it is assumed that illusory images are
real. This interpretation applies only to the Phantasmal Force
family of spells. Some illusion/phantasm spells, such as Spook
and Phantasmal Killer are obviously mental attacks.
Purely audible illusions, most of which are cantrips, are harder to
interpret. Officially, a successful saving throw (or disbelief roll, in
the case of Audible Glamer) makes the target unable to hear the
sound. This seems like a mental attack. As discussed above, however;
this is inconsistent with what is known about mental attacks and
defences. Furthermore, it is unlikely that audio-visual illusions such
as Improved Phantasmal Force would have real visual images but
mental sound effects. A more reasonable interpretation is that auditory
illusions produce real sounds. A successful saving throw reveals that
the sound's cause is magical, but does not make the sound inaudible.
Illusory damage: mind over matter
The greatest source of conflict about illusions is their ability to do
damage. How can an image with no substance hurt anyone? The answer is
that it can't - but the victim's mind can.
Even in the real world, human reactions to fear or stress are not always
healthy. People who narrowly escape injury are often left weak and
trembling. Many faint; a few actually die of fear. Luckily this mental
trauma is usually short-lived. The victim looks himself over, sees that
he is unhurt and begins to feel better.
With illusions, the victim gets no such relief. Consider a typical
case: John the Stealthy sees the white-hot flames of a Fireball
erupt about him. This is upsetting in itself, but in addition, John's
clothes and hair vaporise as he watches, and his skin blisters and chars
before his eyes. Needless to say, John is going to be pretty shaken up
by the experience. Illusions that depict wounds with images of blood
and gore should leave any believer weak and shaken, corresponding to a
loss of hit points. Some victims would be rendered unconscious, and the
weak-hearted few might even die. Note that the damage potential of
illusions comes from both the mind and the eyes acting together. Thus,
creatures which do not see the illusion due to blindness, sleep or
unconsciousness cannot be harmed. Likewise, unintelligent creatures
such as dinosaurs, insects ,and slimes cannot be damaged directly by
illusions because they are too stupid to understand that they should be
hurt. Indirect harm is still possible, of course. For example, a
skeleton is too mindless to be harmed by an illusory Fireball,
but would take damage if the creature fell into a pit concealed by an
illusion.
Disbelief: denying the image
The essence of an illusion's power is belief, so a good defence
against illusions is disbelief. Successful disbelief occurs when the
observer is convinced that what he sees is not real, despite the
evidence of his senses.
For disbelief to be possible, there must be differences between each
illusion and the reality it simulates. The scales on a dragon may be
the wrong shape, or a soldier's feet might not touch the ground.
Spell-casters of higher level and greater intelligence can minimise
these differences, but an intelligent observer might attempt to
disbelieve. This need not be a conscious act - The viewer might
suddenly realise that the troglodyte he is fighting doesn't smell bad
enough to be genuine.
Disbelief is automatic if a viewer touches the illusion and it doesn't
respond realistically (eg. if someone swings a sword through a goblin
without even getting its attention). According to the description of
Phantasmal Force in the Players Handbook, "the illusion
lasts until struck by an opponent - unless the spell-caster causes the
illusion to react appropriately." If the illusionist is controlling the
image and causes it to react - blood spurts, rock chips fly, a character
appears to walk across a bridge, etc. - then disbelief is not
automatic.
Subconscious belief
One problem with illusions is deciding when characters should try to
disbelieve. Player characters should have a chance to notice errors,
but the illusion should not be obvious. To meet this need, some DMs
give lengthy descriptions of every object and creature the party meets.
This technique taxes a player's patience and burdens the DM with
excessive preparation time. Alternatives are to never give the party a
clue, or risk giving everything away with clues like "John thinks the
toad hops funny."
The disbelief system presented here applies both to PCs and NPCs; it is
based on the idea of subconsciously detecting and interpreting errors.
Detecting an error means that the character's mind notices something
unusual about the image - perhaps the way a monster moves. Interpreting
an error means finding some way to explain it; is the creature an
illusion, or is it just limping? Detecting errors and interpreting them
are different events. More intelligent and skilled illusionists make
fewer errors, and more intelligent viewers are better at spotting
errors. Interpreting an error as an illusion (ie. disbelieving) is a
function of experience and willpower. To see how good the image is, the
DM subtracts a secretly rolled d20 from the sum of the illusionist's
intelligence and level. The result is called the image quality. Any
viewer whose intelligence is greater than the image quality detects an
error, and that viewer's subconscious immediately tries to disbelieve
(ie. interpret) the image. The disbelief roll is a standard saving
roll vs. spells, with magical attack adjustments for wisdom. Like the
error detection roll, it is secretly rolled by the DM.
If the illusion-caster is not a member of the illusionist class, the
character's level for the purposes of the image-quality roll is less
than his actual level. The effective level for magic-users is two lower
than the actual level, just as for the fourth level magic-user spell
Dispel Illusion. A high level thief has a 25% chance of failure
with a scroll, so a thief's effective level is five lower than his thief
level. Creatures that use magical items to create and control illusions
are effectively zero level, unless they can also cast illusion spells -
in which case, a monster's hit-dice equate to illusionist level
directly.
Each sufficiently intelligent viewer has an automatic chance to
disbelieve when he first observes an illusion. For example, a 7th level
illusionist with 15 intelligence casts a Spectral Force
which is seen by a fighter, a magic-user, and a thief. A 20-sided
die is rolled and comes up 9. Subtracting this from the illusionist's
level and intelligence yields an image quality of (7+15-9)=13. The
fighter's intelligence of 9 is too low, but the magic-user's is 17 and
the thief's is 14. Thus the magic-user and the thief, but not the
fighter, have detected errors and get an automatic chance to disbelieve
the illusion.
Normally, there is only one subconscious attempt to disbelieve for each
sufficiently intelligent viewer. More attempts to disbelieve occur if
the illusion and the viewer come into contact (eg. an illusory
Fireball bursts among the party, or a character touches an
illusory wall). If only one important sense component (usually touch)
is missing, then a disbelief roll is made for viewers whose intelligence
is higher than the image quality. If more than one important sense
component is missing, the viewer gets a disbelief roll regardless of
intelligence. If disbelief fails, the viewer does not recognise the
illusion. Successful disbelief means that the viewer recognises the
illusion, and any illusory attack in progress causes no damage to the
viewer. Damage remains from any previous attacks which were not
disbelieved.
Which sense components are important depends on the image, the viewer
and other conditions. For example, When touching a wall created by
Phantasmal Force, touch is the only important missing sense. The
same illusory wall would be missing two important senses if the viewer
knocked on it to produce a sound. A Fireball involves
mainly visible, tactile and thermal senses, only one of which is missing
from a Spectral Force spell. Blows struck by illusory monsters
should include sound as well as touch. Dragons have an acute sense of
smell (Monster Manual, page 29), so smell is important for any
illusion which affects a dragon.
To continue the scenario above, let us assume the magic-user and the
thief failed to disbelieve the illusion at first sight, so all
characters believe the image. The illusion depicts a blue dragon which
breathes on the three. The lightning breath normally includes visual,
auditory, tactile and thermal aspects. Only one of these, the tactile
sense, is missing from the Spectral Force, so only the magic-user
and the thief get a subconscious attempt to disbelieve. The magic-user
succeeds, so she takes no damage and knows that the dragon is an
illusion. If she can communicate this to the others, they receive a +4
on any subsequent attempt to disbelieve. The fighter and the thief
attack the dragon with swords. The thief hits, so he gets another
automatic chance to disbelieve. If he succeeds, he is still wounded
from the dragon's first attack.
Beings with superhuman intelligence automatically detect some illusions.
According to Legends & Lore, page 7, beings with 19 or higher
intelligence automatically detect first-level illusions; those with 20
intelligence detect second-level illusions, etc. This means that
Phantasmal Force cast by a magic-user is a first-level illusion,
not third. Cantrips are zero-level spells, so illusion cantrips are
automatically detected by creatures with 18/51 or higher intelligence
(as might be obtained using wish spells, as per the DMG,
page 11).
Conscious disbelief
The disbelief attempts described above occur automatically, secretly and
instantly in game time). Player characters, of course, may attempt to
disbelieve at any time. To prevent a chorus of "I disbelieve!" on every
encounter, explain that a character can do nothing else during the round
he attempts to disbelieve. This is because the character hasn't spotted
anything wrong with the image, and must spend time looking - looking
hard - for errors, and deciding whether any errors are
significant. For example when blasted by some magical effect, a
character may attempt to disbelieve voluntarily. If successful, the
character recognises the illusion and takes no damage. If the disbelief
fails, or the effect turns out to be real, the character receives no
saving throw, because while everyone else was jumping out of the way, he
was standing there looking for errors in the image. Likewise, if the
character chooses to disbelieve an attacking monster, the character may
not attack and may not use shield or dexterity to defend against that
monster during that round. The character can still defend against
attacks from other opponents.
The character is always free to disbelieve new developments when they
affect him (eg. a fighter who has already attacked an orc during a
round may nonetheless choose to disbelieve if the orc suddenly uses a
fiery breath weapon). Spell-casting is not disrupted if the
spell-caster successfully disbelieves an attack either consciously or
subconsciously.
Conscious disbelief requires only a save vs. spells. A character (or
player) who decides to disbelieve has already noticed something peculiar
or has been told the image is an illusion, so image quality is
irrelevant to the decision. Conscious disbelief is often necessary for
thick-witted characters, since their low intelligence is unlikely to
exceed any reasonable image quality. A conscious attempt at disbelief
in no way reduces a character's chance to subconsciously disbelieve.
A special form of conscious disbelief occurs when a clever or desperate
character decides to close his eyes. Unable to see, the character might
be unharmed if a pending attack is an illusion with only visual
components. This is a reasonable tactic for someone like a 1st-level
thief who thinks (or hopes) that the huge red dragon in front of him
might be an illusion. After all, he is unlikely to make his disbelief
roll either consciously or subconsciously, and saving vs. breath weapon
would only change the texture of ashes he leaves behind. The character
must close his eyes before the DM announces an attack; if he waits to
see what the attack is, he will be affected by it. Naturally, closing
one's eyes in combat gives opponents who are not illusory lots of nasty
ideas.
Modifiers to disbelief rolls
Many factors affect the difficulty of disbelieving an illusion. In
general, anything which increases the doubt in a viewer's mind affects
the chance to disbelieve. The list of modifiers in the table with this
article cannot be complete, but it should give a general idea. All
factors are assumed to provide bonuses or penalties to the disbelief
roll. Some might be more appropriate as modifiers to the image quality,
but that would merely complicate matters.
For example, illusory creatures popping in from thin air give viewers +1
to disbelieve. An illusory creature unharmed by a lightning bolt would
add +2 to disbelief rolls.
Damage from illusory spell effects
Unlike normal spells, an illusory magical effect can be repeated from round to round,
doing additional damage. Fortunately, this effect is self-limiting, since an intelligent
victim usually receives a disbelief roll for each attack. Otherwise,
the effect only stops when the illusionist is attacked, or decides to
stop.
A single illusion spell can create only one kind of effect. To switch
from Fireballs to Lightning Bolts, the illusionist
must cast a new illusion.
Illusory creatures in combat
An important issue is that of how many separate creatures can one
illusion include. Can a 6th-level illusionist conjure up an army of
20th level paladins, each armed with a long sword, +5 holy avenger? It
could be done, but the illusion might not be very believable if any
fighting takes place. In combat, the illusionist must control each
illusory being's attempts to hit, simulate injury on both the bogus
creature and the opponent, and control attempts to dodge opponents'
blows. When a blow is not dodged, the illusionist must create a
convincing image of bloody death. Each of these efforts taxes the
illusionist's skill, concentration and stamina.
An illusionist can control illusory creatures with as many hit dice as
he has levels (eg. a 6th-level illusionist could create and control six
1-HD beings, one 6-HD being, etc. This limit reflects the ability of
the illusionist to control the many details of combat. Higher-level
illusionists have more skill. Human and demi-human creations can be
used; the difference between illusory 1st-level fighters and 10th-level
fighters is the skill with which the illusionist handles them in combat.
Created creatures may differ in equipment, hit dice and tactics.
If the illusionist exceeds the hit-dice limit, then details are being
neglected and all opponents get an automatic attempt to disbelieve
during every round of combat (this in addition to any other disbelief
attempts to which the viewers may be entitled). The illusionist may
control twice as many hit-dice of illusory creatures if none of the
creatures are in combat (this may be used as a bluff).
The illusionist must roll to hit for each illusory being's attack, since
he can control the attempt to hit, but not the victim's attempt to dodge
or parry. Use the appropriate attack matrix for each creature's
hit-dice or level. High-level illusory cavaliers and fighters get
multiple attacks appropriate to their level, but weapon specialisation
or bonuses for strength, weapon of choice, or race do not apply. Damage
is determined randomly, as appropriate for the creature or weapon.
Sufficiently intelligent opponents get a disbelief roll whenever the
image hits or is hit.
The armour class of illusory creatures is the same as for normal
creatures of the same type. Illusory warriors may be equipped with
whatever armour the illusionist chooses. No magical or dexterity
bonuses are allowed unless the total illusory hit-dice are reduced by
the amount of the bonus.
The DM should decide how the total hit-points for all creatures in an
illusion are determined (eg., a random roll, 1d8 for fighters, 1d10 for
monsters, etc., or always 5 hp per hit-die). The illusionist assigns
these initial hit-point to individuals as he sees fit, since the
illusionist decides how much effort is expended in each creatures
defence. When an illusory creature reaches zero hit-points, the
illusionist's mental fatigue is so great he cannot make the creature
avoid the death-blow. If the creature fails to fall dead, all viewers -
not just direct opponents - attempt to disbelieve every round that the
creature remains active.
Armour class and hit-points are rather fuzzy concepts for
semi-invulnerable creatures such as lycanthropes and for regenerative
creatures such as trolls. Disbelief rolls are made whenever the
creature should be hit - thus if a viewer strikes a bogus werewolf but
appears to do no damage, he still receives a subconscious attempt to
disbelieve (regardless of intelligence, if more than one sensory
component is missing). Regeneration reduces the initial hit-points
available. For example, a 9th-level illusionist conjures a troll; 45
hit-points are rolled. The illusionist gives the troll 25 hit-points
initially. If the troll is wounded, up to 20 hit-points can be restored
by regeneration. Beyond that, the troll cannot regenerate.
The illusionist may choose to combine an illusory magical effect with
illusory creatures (eg. a bogus magic-user could appear to cast a
spell). In such a case, the level of the magical effect must be
subtracted from the hit dice available to the creatures.
An anomaly of illusions in melee is that illusory creatures do not
usually get parting blows when an opponent turns to flee. The opponent
has turned his back, so he cannot see the illusion and therefore cannot
normally be hurt by it. Likewise, a purely visual illusion of a thief
cannot back-stab.
Effective use of illusions in combat requires the illusionist to
concentrate on the details of the battle. The spell Programmed
Illusion can create an illusion of creatures performing some action,
but cannot react to opponents. Similarly, if the illusionist stops
concentrating on an Improved Phantasmal Force or
Spectral Force spell, fighting degenerates to programmed action
for the duration of the spell. Anyone who strikes a programmed creature
recognises the illusion. Even a programmed dragon breath would be
relatively harmless because there would be no way to simulate injury.
Each victim receives an automatic attempt to disbelieve; those who fail
take only half the normal damage. (These limitations do not apply to
the spell Shadow Monsters and its descendants, which create
semi-real monsters that react to opponents.)
Non-combat illusions
The effectiveness of illusions in combat is usually limited by
thechance for victims to disbelieve whenever damage is done. Illusions
are often more effective if used to confuse or mislead rather than
injure. In such cases, disbelief becomes irrelevant.
Illusory magical items
Illusions can include magical items which produce visible effects (such
as wands). The power of these devices is limited by the illusionist's
level, just as for an illusory spell. A 1st-level illusionist can
create an illusory wand of Fireballs, but it can only do 1d6
hit-point damage. The level of the magical item is subtracted from the
total hit-dice the illusionist can control in melee (eg. a 6th-level
illusionist could blast opponents with 5-HD Lightning Bolts from
an illusory wand wielded by a bogus 1st-level spell-caster). Illusory
magical items can enhance an illusion's credibility.
Illusory magical weapons are also possible. If a fighter hits an
elemental and causes a visible wound, the elemental is likely to
conclude that the fighter's weapon is magical - even if both the fighter
and the wound are illusions, and the illusionist doesn't know that
magical weapons are needed to hit elementals. The exact weapon bonus
would be difficult to guess from the image, so the DM should roll 1d4 to
see what bonus the victim thinks the weapon has. Add this number to the
illusionist's damage roll. Note that the number must be sufficient to
hit the creature (eg. at least +2 for an elemental). The "weapon" has
no actual bonus, so the illusionist's unmodified "to hit" roll must be
sufficient to hit the victim.
Invisibility
Some players may want to use Phantasmal Force as an
Invisibility spell. Both spells belong to the class of
illusion/phantasm magic, but they are quite dissimilar. Phantasmal
Force is a quite general spell that is maintained by
concentration and can be used to attack; Invisibility is highly
specialised, requires no concentration and is dispelled by aggressive
acts.
Despite these differences, the DM may decide to allow illusory
invisibility. If so, the result will differ from the
Invisibility spell. Illusory invisibility lasts only as long as
the caster concentrates (or a for few extra rounds if Improved
Phantasmal Force or Spectral Force is used). The area of
effect and the range are the same as for Phantasmal Force.
Inanimate as well as animate objects could be made invisible. Many
objects could be made invisible so long as all remain in the area of
effect. Unless its retinas remain visible, an invisible creature is
effectively blind because light does not reach its eyes. Disbelief will
not reveal the hidden object's identity, but will let the viewer know
that he sees an illusion.
True Invisibility is a good defence against illusory attack. The
illusionist cannot create visible wounds on an invisible victim. Indeed
the illusionist does not even know when the victim has been "hit", so
illusory attackers do not react correctly. If the invisible creature is
hit by an illusion, treat it as a programmed attack; The invisible
creature automatically attempts to disbelieve, and only takes half
damage if disbelief fails.
An illusionist cloaked in normal Invisibility spell is revealed
when attacking, even if the attack is carried out by an illusory
creature. Merely casting an illusion does not constitute an attack.
Only when the illusion is actively used to damage its viewers will the
illusionist's Invisibility be dispelled.
The system presented here solves some problems and helps bring illusions
into balance with other forms of magic. Disbelief is handled
consistently. Damage and complexity of illusions are proportional to
the illusionist's skill. Low-level illusionists can befuddle stupid
opponents or damage weak ones; high-level illusionists can fool nearly
anyone. Members of the illusionist class can use better illusion spells
to damage powerful opponents.
No system can cover every possibility that can arise when creative
players use a spell like Phantasmal Force that "can create the
illusion of any object, or creature, or force....".
Decide what the principles of illusory magic are in your campaign, then
make sure players are aware of them before illusions are used. When
situations come up which the system doesn't cover, keep the game
friendly by not using questionable techniques until you reach some
agreement on how such techniques will work. Enjoyment of the game is a
co-operative venture; with a little understanding from the players and
the DM, illusions can bring a lot of spice to an interesting world.
[For another view on saving-throw modifiers on illusions, see
"Illusory Solutions," by Matt Battison, in the February `88 issue of
Dragon ¨ magazine.]
Illusion's condition Saving-throw modifier Illusion cast by an opponent believed to be an illusionist +1 Illusory creature appears from thin air +1 Illusory creature or effect is the same as one already -2 used by opponent Illusory situation is obviously inappropriate (eg. orcs +2 and elves working together, Fireball underwater.) Illusion lacks important sensory component +1/missing sense Illusion is of "normal" creature, but is unharmed by +1, +1/weapon plus normal weapons Illusion is of "normal" creature, but is unharmed by magic +2 Illusion is of a stationary object (eg. a wall) -1 Illusion is seen poorly (eg. through fog or over distance) -1 to -4 Illusionist has never seen creature or effect which he depicts +4 in real life Illusion is viewed in confusing context (eg. in a life-size -1 to -4 model of Escher's Relativity, or in the Plane of Pure Chaos) Illusion is unreasonably powerful (eg. dragon in 2nd-level MU's +1 to +4 castle) Illusion depicts large object in small space (eg. hydra head +1 poking out from 10' long dead-end corridor) Viewer's ally claims to have disbelieved illusion +4 Viewer is a cavalier +2