Homebrewed Handling of Illusions

Illusions (Illusionist spells in particular) and the way they are intended to be handled are as enigmatic as they are wonderful in their engenderment of creativity and diversity in roleplay. Experienced AD&D players can get quite liberal in their attempted use of illusions and it requires an equally experienced DM to properly reign in any overzealous attempts.

Personally, I like to have a framework to fall back upon with common events such as illusionist spells such as Phantasmal Force. For one, it allows for the perception and actualization of fair judgement from one character/spell to the next. It also sets expectations for Players in how their illusions will be handled. Thus, I created the Illusions module.

Illusions are tricky business in AD&D. I have established a system for dealing with some of them, most notably the (Improved)Phantasmal Force spell. This system is an amalgam of ideas from the DMG, “Dragon” magazine, and other brilliant DMs I have discussed this with in the past. Special Mention to Frank Mentzer who gave me some insight as to how some of the OGs handled the subject.

How it Works

Upon first view of an illusion, and again upon first physical contact with the illusion, the DM secretly attempts on behalf of the defender a Detection roll. If Detection of anomalies in the illusion is successful, a Saving Throw is made against Mental Attack(Wisdom Bonus applies) Spells to see if the Illusion is properly identified as not real, or Disbelieved. If Disbelieved, no more damage is incurred by the defender but any previous damage remains.

Players may consciously/expressly declare they think something as an illusion. If it is not in fact an illusion but real, no Saving Throw is allowed even if ordinarily allowed as the Character took no actions to steel themselves against the attack. If it is in fact an illusion, another Detection Roll is permitted but no other action may be taken this Round as the Character is using this Round to actively and carefully inspect the alleged illusion for signs it isn’t real.

For Detection rolls, Image Quality is first established in our DM module by adding the spellcasters Intelligence score and Level, adjusting for spell caster Class(Illusionist -0; -2; Mage -2; Thief -5;), and subtracting a random d20 roll. If the defender’s Intelligence score is higher than this Image quality, the defender successfully Detects anamolies within the illusion.

Upon Detection, the defender is entitled to a Saving Throw, adjusting for Wisdom-based Mental Attacks defense. Bonuses are added or subtracted to the Saving Throw d20 roll for factors noted in the module such as, was the spellcaster seen casting a spell or did the illusion pop into view from out of thin air. A successful Saving Throw means the illusion is Disbelieved and no longer effects the defender.

An illusion caster may only make an illusion of something he/she has experienced or seen before. A caster likewise cannot simulate something of a power(level) that is beyond their capacity(level).