Magic resistance is a hidden property which governs how often a particular type of monster ignores the effects of certain spells, wands, and mindcraft. The percent chance for a monster with magic resistance to ignore an effect is reduced by one point for every two of the PC's experience levels; otherwise, the chance for each type of monster is fixed.
Magical effects fall into three general categories: effects that can only be ignored with magic resistance, effects that can be ignored without magic resistance (magic resistance increases the chance), and effects that cannot be ignored with magic resistance. Note that monsters may be completely unaffected for other reasons, such as an elemental immunity or resistance to death rays.
Rough ranges of magic resistance used on individual monster pages:
Effects only ignored with magic resistance Edit
These effects can only be ignored with magic resistance. Monsters without magic resistance must be completely immune to the effect to avoid being affected.
Damaging bolts Edit
For Acid Bolt, Fire Bolt, Frost Bolt, Lightning Bolt, Magic Missile, and their wand counterparts, magic resistance is indicated by a seems to shrug off message. Elemental immunity is indicated by a resists message.
Other lethal bolts Edit
For healing spells, magic resistance is indicated by a without sensing any effect message. For Bless, magic resistance is indicated by a shrugs off your soothing touch message. For Destroy Undead, magic resistance is indicated by a resists your invocation message.
Teleportation, Slow Monster, and Invisibility Edit
Telepathic mindcraft powers Edit
For mind blasts and mind waves, magic resistance is indicated by a resists message. For confusion blasts and waves, magic resistance is indicated by a resists your mental incursion message; immunity to confusion is indicated by a you sense a truly strong will resisting your efforts message. For teleport other, magic resistance is indicated by a you don't manage to penetrate the mind message.
Effects ignored without magic resistance Edit
Every monster has a base chance to ignore these effects. Magic resistance still applies, so magic resistant monsters are less likely to be affected. It is also possible for monsters to be completely immune to some of these effects.
Debilitating bolts Edit
For Stun Ray, Wand of stunning, and Wand of paralyzation, both base resistance and magic resistance are indicated by a seems to shrug off message. There is no special message for monsters which are immune to stunning and paralysis.
Petrification, Calm Monster, and Scare Monster Edit
For Petrification, base resistance, magic resistance, and immunity to petrification are all indicated by a resists your spell message. For Calm Monster, base resistance is indicated by an appears to be rather bored message; both magic resistance and immunity to calming are indicated by an ignores your spell message. For Scare Monster, base resistance, magic resistance, and immunity to scare are all indicated by a doesn't seem to be impressed message.
Potion of exchange Edit
For Potion of exchange, both base resistance and magic resistance are indicated by a dodges the potion message; immunity to exchange is indicated by a nothing happens message.
Effects not subject to magic resistance Edit
These effects are completely unaffected by magic resistance. Monsters must be completely immune to the effect to avoid being affected.
Ball spells and Burning HandsEdit
Know Alignment, Mystic Shovel, and healing spells Edit
Telekinetic mindcraft Edit
For telekinetic blasts, immunity to the effect is indicated by a simply passes message.