Many of the magicks in The Compendium are noted as being able to “Oppose” assorted other magicks. Such magicks are said to Oppose when their effects embody opposite influences, or close enough to opposite as to make little or no difference. This is true when they manipulate opposing elements such as fire and water or earth and air. Most charms are presented with their opposites in the descriptions, as they are sometimes the two sides of the same skill (i.e., whether the Art is used to freshen a piece of fruit or make it rot are flip sides of the same coin according to the Law of Polarity in magick, therefore, the same skill).
When an charm is cast upon the dweomer of its opposite, it suppresses its effects, subtracting its POT from it.
The power of any given cantrip, aria, spell, prayer, rite or ritual of the same Sphere of Power and the same POT are considered equal in power, for all intents and purposes. If one opposed the other, each would cancel out the other’s effect, DUR in the end determining which dweomer would outlast the other.
Opposing charms may be laid one atop the other until one has eliminated or reversed the effect of its opposite with a total POT greater to that of the target magick.
When practitioners face off, the charms woven in opposition can be built up like the layers of an onion, often devolving into a simple test of stamina to see who can handle more POT (has greater skills) and outlast whom, because dispelling gets a little more complicated.
Charms that are noted as being Opposed can always be used as Dispelling charms, as follows.
While the procedure for determining the outcome of an attempt at dispelling is similar to that used in comparing magicks in opposition, it is carried one step further. Where dweomers in opposition try to suppress or mask one another’s effects, a caster attempting to dispel a dweomer is actually attempting to loosen and break the pattern of Power of which it is composed, to completely unbind it and permanently disperse it altogether.
A practitioner must use a Dispelling for the Art used to create the target dweomer in order to accomplish this task, or any charm noted as Opposing the target dweomer but, again, cast by means of the same Art. The Dispelling itself must first be successfully cast, according to normal procedure, before any attempt at Dispelling is resolved.
This is handled as a Contested Roll, in the same manner as attuning a magick, cache, Touchstone, etc., in a series of rolls. Each roll assumes a CS of time has passed. The contest continues until the Dispelling practitioner either succeeds or fails. He may not break off and start again once he has engaged.
The AV to Dispel an existing charm is equal to [(MGT att. mod.) + (applicable Dispelling SL) + (1 per 4 points of POT)].
The DV to Dispel an existing charm is equal to that charm’s [(SL) + (caster’s MGT att. mod.) + (1 per 4 points of POT)].
If the Dispelling is successfully cast but fails to actually dispel the target dweomer, it has no effect whatsoever, except to trigger any Wards or other protections wrapped around the dweomer he is attacking, (if applicable). Dispellings that fail to succeed against their target dweomers simply dissipate. They do not suppress as do those cast in Opposition, since that was not the intent behind their weaving.
When a character wishes to dispel a dweomer that has an AoE of a measured physical surface or region, his Dispelling charm (whether a true Dispelling or an Opposing magick used for that purpose), must be cast upon the “nodes” of the dweomer at the center of the AoE. The “nodes” are the knot(s) formed by the pattern of a charm when loosed, where it is anchored fast to the material world. This is the point from which the center of the AoE is measured. This includes such magicks as “Cloud of Fog” or “Cloud of Dust;” “Alarum Charm;” “Circle of Silence;” “Circle of Light/Darkness;” “Circle of Glare/Gloom;” “Temperate Charm;” “Ensorcel Fog & Mist;” “Ice Slick” or “Oil Slick” or “Slick Stone;” “Phantom Maze;” “Plant Maze;” “Ravenous Mire;” “Rainstorm;” “Snowfall;” “Rain of Poppies;” “Reign of Seasons,” and so on.
The nodes can be located with a “Reveal” if the practitioner looks for them once he has discovered the field of magick, providing the nodes are within sight, or they may be “felt” through the Sense Magick Spirit Skill.