Magic Resistance (ArM4)
Maintainer's Note: This article pertains specifically to the Fourth Edition mechanics for Magic Resistance and Parma Magica. In Fifth Edition, the rules are quite different.
Parma Magica is a topic that has long been debated on the Ars Magica list, and in an attempt to prevent too many more flames, I submit to my sodales the following. Please realize that this is how Parma Magica is defined by ArM4. It does not cover all situations and you will have to make rulings based on your own judgment of how parma and magic resistance work. I only ask that you do not try to claim that your house rules are anything but local rulings.
Principles
- Parma Magica literally translates to 'magic shield.' It is defined in ArM4 as an Hermetic skill, and its description is found on pages 55, 72, and 73 of the 4th ed. rules book. More details can be found on pages 69-74 of the Wizard's Grimoire, Revised Edition (WGRE).
- Parma Magica is a form of magic resistance, and acts per the same rules as other magical resistances, except that it must be reinstated at sunrise and sunset. NOTE: though this is a 'ritual' it is not a 'Ritual Spell' in the hermetic tradition.
- Resistance may be raised and lowered at will for its duration.
- Resistance only covers the target and anything he wears or holds in his hand.
- Just touching something does not convey protection.
- Parma Magica does not protect against spells that have a range of Personal.
- Parma Magica protects the magus from spells and magical effects that either directly attack the magus, or attack through a magically created media. If a natural result of a spell attacks the magus (someone PeTe the wall under his feet, for example), then the magus will still fall and take damage from that fall unless he is able to avoid it in another way.
:Direct attack: A direct magical attack is any spell or magical effect that targets the maga specifically. Thus most Perdo, Mentem, Muto, and Rego spells are considered a direct attack. "Healing" spells (Creo) also target the individual, and are thus resisted unless the maga drops her resistance.
:Magically created medium: A magically created medium includes anything created by magic with a duration other than Instant or Permanent (WGRE 73). This includes, rocks, wolves, fire, lightning, towers, and insects.
NOTE: Canon in no way says whether or not a Muto'd object (an arrow made from smoke, for instance) is a magically created medium or not. This should be determined in your saga, realizing that YMMV.
- You cannot resist spells that change your environment. Neither can you touch, hold, or hit an enchanted object or spell to dispel it. Spells that change your environment include (but are not neccessarily limited to):
' Intellego spells used to view an area, as long as it does not target the caster directly (though a successful resistance roll will let the magus know that he is being watched through magical means). ' Muto spells that change an object other than the resisting magus. Thus a pebble turned into a boulder will not turn into a pebble again when it hits parma, nor will a nest of vipers that has been turned into a pebble. Whether or not it is resisted is not canonically defined and should be decided by the storyguide. ' Perdo spells that destroy something other than the resisting maga. For instance if it destroys the wall on which they are standing or a piece of the branch above their head. ' Rego spells that move things about that may cause other, natural events. For instance if an axe were used to chop down a tree to fall on the magus.
- When Parma Magica protects you from a spell it does not, necessarily, dispel the spell itself. Magically created animals may not attack, or may pop when they do. Flames may peter out or roar past the magus who is protected from their heat. A ReTe rock may stop an drop harmlessly at a maga's feet or be deflected elsewhere. As long as the effect is "dramatically appropriate" (WGRE 74) it is proper.
- Finally, we get the nitpicky details. Some would say that a magical bridge should be resisted by the magus, thus causing them to fall through. David Chart, co-author of WGRE and a contributing author to ArM4, made clear his opinion on this issue: "Magical bridges don't disappear when magi step on them because nothing does. Magi don't have trouble walking on magical bridges because the Parma just stops the impact being damaging, and it wouldn't be anyway."
There are many other controversial examples that are omitted here. That is because much of this is left to the storyguide to decide how powerful parma should be. Even the bridge debate is opinion. Also note that anything above may be changed to fit the storyguide's vision of their gaming world.
Remember that YMMV. Parma is a powerful tool invented by Bonisagus, and most characters won't understand how it works anyway. Use it as a tool to make your adventures more fun and enjoyable, and don't get so bogged down in it that you lose sight of the fact that it is only a game.
["-- Joshua Badgley]