Question About Perdo Vim and Non Hermetic Effects

So I have a player who is making an Anti mage. hes strong in Perdo Vis and intends to use Parma Magica and Perdo Spells to counter anything he comes across.

My question is this:

In regards to non hermetic spells how do these work? how do I calculate the level or type of perdo vim spell needed to counter a supernatural ability? like Entrancement? how about magical powers used by creatures or other types like infernal or fairy?

I recently had a situation where a villain used an infernal supernatural power to hold someone in place and he wanted to dispel it. I just went with it not knowing how to calculate such effects, assuming it was basically a rego corpus effect however as its a supernatural ability it has no magnitude or spell level to counter. I've also found the problem that basically any low level spell can be easily countered by spontaneously casting a low level perdo vim spell. how do i deal with this? it's even worse if its a hermetic spell cause then he can counter it better. or if hes worried he can fatigue on the spontaneous cast and make it higher too, and if he really pushes it he can always roll well and use confidence to boost it.

Example Spell: Spontaneous Casting Perdo Vim, Dispel Level 15 (base 5 +2 voice) Dispels any effect up to level 15 (5 + 4 mags = 25)/2
(perdo 10 + Vim 15 + stam 2 + stress/5) Means he can guarantee a 5 without a botch which means he takes a fatigue and it happens at -10 pen.


I don't understand one part of your problem... That part being, you wondering how to "deal with" how easily he blows away weak effects. Weak effects don't require as strong of magic to blow away as strong effects require. Kind of a duh statement. If the effect is weak, let him blow it away easily.

As for your other concerns... Well, the spell Unravelling the Fabric of (Form) mentions that it has non-Hermetic variants. So depending on how powerful you feel like making it, either have it apply to entire magical traditions, or apply it to specific Abilities and Hedge Magic Forms. The second option feels more thematically appropriate to me (with certain exceptions, like the elemental Forms being synonymous with the Elementalist Forms), but YSMV. As for how to adjudicate effect levels for non-Hermetic stuff...

Anything with a TeFo is easy, as their levels can simply be treated as Hermetic levels for purposes of dispelling difficulty. As for straight-up Supernatural Abilities... Well, I have two potential philosophies on this, though the subject has never come up in my games in a lot of detail. My own personal thoughts are that mere singular Supernatural Abilities are much weaker than the focused, complex, and methodical magics woven during TeFo combinations and Folk Witch kitchen work. By that philosophy, a "spell level" equal to the effect's Ease Factor is appropriate. This also seems appropriate if you compare the calculations for determining Penetration for Supernatural Abilities with those for full Traditions; they're basically identical, except that "spell level" is replaced by "effect Ease Factor." This method makes simple Supernatural Abilities quite easy to dispel.

Some people, however, don't subscribe to that philosophy, instead vouching for the idea that Supernatural Abilities should at least be equal in power to Hedge Magic, if not Hermetic or Rival Magic. In that case, simply multiply the Ease Factor by either two or five; two to make them about as resistant to destruction as Hedgie stuff, five if you're trying to be funny by making top-end non-Witch Supernatural Ability users have effects that require specialized middle-aged magi just to dispel them. (Hint: No magical ability available to the un-Gifted outside of a tradition should ever have that much power.)

Hope I helped.

I completely agree on the supernatural abilities, they are pretty low level effects. some have penetration but that's not the same as being resistant to dispelling magics.
My Larger concern is with the idea of spontaneously casting a form specific perdo vim spell.

Step 1 does he have to know what type of magic it is? or what kinds of specifics should he know. and if not he can still cast the dispel all version.

with a base pool of 27 (perdo vim and stam) even not using fatigue he has a 5 and with fatigue he has a 15, which with the way the dispel works means he can dispel 15 and below without fatiguing and 25 and below if he does. assuming hes willing to take fatigue from being -10. not including his roll or any other factors like vis use confidence or aura.

Which basically means to have any antagonist that can have an effect that isn't immediately dispelled against him has to be over level 25, and possibly higher if he really wants it gone.

I'm all for letting my players do what they are good at but doesn't this effectively make him perfect against everything? if its magical in any way he shuts it down, and then can use his magic to deal with it. (even low level spells are effective when you can't do anything about it) I just feel a little lost on how to bring a challenge to this character. I could ask him not to play it or make other concessions I'm just confused if this was the intended effect of perdo vim.

Oh, you don't have to worry too much about that challenging thing. In order to spont any effect with variable Form, you have to know the Form in question with some degree of intimacy. This varies from troupe to troupe, but if you want to keep him from blowing away any individual thing, a pretty reasonable interpretation of needing to have "some knowledge of a type of magic (but not necessarily know how to use it)" would be to use the Hermetic apprenticeship as a guideline and say that they need to study the magic for a season in order to understand it well enough to use PeVi against it. It wouldn't necessarily be restricted to one little subset of magic (if you studied, say, a valid (Hedge Magic) Theory book for a season, you might have "some knowledge" of all the magical abilities of the tradition) but if you do study multiple things then what you do study must be linked in some way, and you need to spend a full season on it regardless of how much or little there is to learn about. That means that, until they've studied other types of magic, your PeVi specialist will only be able to spont-dispel Hermetic magic, which usually won't be a problem because Hermetic spells have very little trouble getting above level 25.

Sure, there's Wind of Mundane Silence, but that's a whole lot weaker than Form-focused dispels, so while he won't have any trouble dispelling Supernatural Abilities and the less skilled among the Hedge Magicians, most middle-aged or older Hedge Wizards can lay down effects that would be way too strong for him to dispel. Which is a good thing, mind you; you don't want Hedge Magicians matching up to your player's PeVi specialist when they're the same age as the PC, because a big deal in Ars Magica is that Hermetic Wizards are superior to all others.

... Oh, and now that I re-read your OP, I think you missed something during your example adjudication. You would need an entirely different spell to dispel Infernal effects than you need to dispel Magic effects. Realms interact weirdly like that. I only hope you didn't let a non-fatiguing spontaneous Wind of Dark Silence fly, because that would only work against effects of level 2 or 3.

On step 1, my thoughts are as follows:

  • Hermetic magic he's going to know about, fine. Even if someone's going out of their way to use Exotic Casting methods, the standard Perdo Vim spells will still work, although you might require a roll in that case for him to realise that they are using Hermetic Magic if it's not obvious from context.
  • Supernatural abilities he'd have to be familiar with the type of ability/magic used to be able to use the more efficient guideline (rather than just using the less efficient "dispel anything" guideline). Familiarity could be based on any of several things. For a hedge tradition, I'd allow knowledge of a single level of their magic theory equivalent to count as familiarity for all their types of magic. Unless the hedge tradition is a major antagonist and he's been doing research, he probably doesn't have that, so I'm mostly including this for completeness. I'd probably allow a Pralixian to count 3 rounds of observation using Comprehend Magic to gain sufficient information to counter that specific ability/Art from then on, although I don't think it's explicitly part of the (major) virtue, and he's presumably not one, making it a bit redundant. After that, I'd start requiring Magic (or other realm, as appropriate) Lore rolls to see if he had the required familiarity - higher ease factors for more obscure abilities.

As far as bringing a challenge to the character, some suggestions:

  • How good is he at fast casting? Granted, if he's making a Perdo Vim countermagic specialist, the answer is probably "pretty good", but high initiative momentary attacks may be able to get through at least some of the time. I think "Fast Caster" is a hermetic virtue it's reasonable to give to Hedge Magicians, and magical creatures can get up to silly initiatives if you take the magical quality "Improved Initiative" enough times. Also, if he's doing a fast cast against a momentary spell (and it'll need to be fast cast to get the spell before it gets him/his friends), are you applying the -10 to casting total and +2 botch dice?
  • Hit him with multiple opponents - can he Perdo Vim all of their attacks fast enough?
  • Have him fight in unfriendly auras. That'll lower his casting total a bit, and make fatiguing sponts a lot riskier if he has to resort to them due to all the extra botch dice.
  • Possibly cheating a bit given he's obviously looking to fight magic users, and not something you want to overuse, but have him attacked by basically mundane attackers (possibly with relics/infernally sourced magic resistance if you want to give them a bit of defence).

I am with Never-ending winter regarding assigning level to non-hermetic magical effect: take the Ease factor.

As it was pointed out, to dispel an on-going effect, you need to know what type of effect it is: which realm it belongs to, which form (in case of hermetic magic) or at least which type of effect it is (entrancement, hex, curse...).
Without this information, it is a bit like trying to quench an fire without knowing its origin: let's pour water on this metal (or oil) fire and see what happens.

So he will need to design a whole set of InVi set to identify the source of power (at least Faerie, Magic and Infernal, I hope he won't try dispelling Divine effect... onthe other hand :smiling_imp: ...). Then if you are lenient, you might let him try a Realm Lore check to identify the spell so he can finally try to dispel the effect.

Now, if you talk about countering a magical effect, he has to do all that in a fraction of a time, so unlikely. Yet again, he can still try to fast cast a PeVi against magical realm: Curse and hope he hit the nail on the head. Except that the edgie was using an Faerie/entracement power.
Since Edge magician, diabolist and so do not have a systematic and formulaic ways to trigger their power, it is nearly impossible except for people of the same tradition to identify which powers they are using when they point their right hand ring finger toward you when blinking with their left eye.

Now, also give to the player an opportunity to shine: if he knows what he is up against, he has done his homework on gathering intel against said Edgie The Baddie III, he knows that he is drawing his power from the Magical realm and his rumored to be able to Curse people and Shapeshift, then he has a fair chance when he will spont his PeVi to know he need to dispel a Curse and go straight for it. Edgie the Baddie III will soon be defunct. And it is normal: for me, there is nothing more powerful than an Hermetic magus who had time to be prepared.

The way you need to present the situation to the player would be the following:

  • Acknowledge that PeVi is the most versatile way to dispel any supernatural powers;
  • Remind him that even to dispel Hermetic magic, he need to know at least the form of the spell he is trying to dispel/counter other wise you will apply the guideline of Wind of the Mundane silence
  • Propose him a list of spell he would need to develop to assist in his quest of becoming an efficient witch hunter (InVi: Perception of the Extraordinary Thread, which allow to detect which Realm is Powering the effect he wants to dispell; then a set of InVi per Realm which would be the equivalent of Sight of the Active Magic)
  • Suggested him set of competences that will help him (Realm Lore, Area Lore)
  • After one suggesful witch hunt which was a much closer call thant expected, have him meet a "professional" with hunter (either another hermetic magus, or even better a priest exorcist (at least somebody outside of the Order), which reckon his ability and willingness to hunt evil-doer and although does not share his philosophy would like to recruit him or train him because he is pragmatic and needs any ally he can find);
  • You can also mention to him rumour about a Mystery Cult which seems to gather exorcist, witch hunter, nightstalker and such, which documents all sorts of supernatural powers, threats and ways to neutralise them, with the possibility to be initiated in some relevant virtue (Detect Holy/Unholy; possibly even Comprehend Magic from the Pralixian, or Ward techniques).

The point is not kill his character concept, but make him understand than generic PeVi is like using a shotgun to kill a fly: very ineffective. There is a reason why there is no PeVi spell called: Dispel Every-Any-All, because hermetic magic cannot do it, the effect would be too diluted. Use the example of Wind of Mundane Silence needing to beat twice the level of the hermetic spell the magus want to dispel to illustrate that, so it will be even worse for non-hermetic effect, and impossible for other Realm-aligned power.

By providing an explanation (based on RAW), proposing ways for his character to achieve his long term goal and enticing him with interesting story hooks, he should not feel cheated.

Great points.

I also spoke to my ars mentor who pointed out spont spells fail if you don't make the target, you can't -10 and take a fatigue.

That being said, can you point me to any rules on how pe/vi spells work against other sources like infernal/fairy? I don't know where to look. someone mentioned its far less effective but i need some concrete numbers.

I have no problems giving him situations where he can shine, and I'm sure he will but i don't want him to become a catch all character that is basically doom to everyone elses plot lines if he happens to come along. and he's beginning to show the others how easy it is, which means they will do it too.

I like making it fairly easy to dispel the supernatural powers that makes sense. and he will have a very hard time countering momentary spells but i was more talking about effects that last. Was just a little sad when he basically unraveled my entire antagonist because he could just undo anything she did. With only the knowledge that the area he was in had an infernal aura.

I think the combo of now knowing he has to use a catch all spell like mundane wind, along with not being able to -10 cast spont spells would've prevented the issue in question. we are still new and learning teh rules so sometimes our misunderstandings cause big issues with the intent of the game.

In the new example:
He tries to counter her infernal spell which is a level 25 effect. He doesn't have a formulaic for this so he fatigues and sponts. He has 27 + say 8 a good roll for a total of 35. divide by 2 and that's 17. He could still cast a 15 pe/vi but now it only counters (base 5 +2 voice) = (5 +4 mags = 25/2 = 13) level 13 effects and below. much more reasonable. so now the level 25 effect is not countered, even when he rolls well.

If he knew what type of magic it was he could use the form specific bonus (which I let him do without knowing the magic type) and cast at level -10

Problem solved i think! perdo vim is still powerful, but definitely not as overpowering as i thought. also if he tried to counter a momentary spell he would not only have to fast cast but wouldn't know the form without other effects like invi

Thank you all!

Uh... I don't think that's accurate. Maybe they meant the character is less effective for having to differentiate? Because the only rule even close to that that actually exists is the Realm separation rule... Which is less an explicit rule and more seems inherent to Hermetic magic. Based on all the guidelines, and PeVi's own capitalization of Magic, any spell that directly affects supernatural creatures or powers as its function (not if you happen to, say, shoot a PoF at a demon) requires a different spell for whatever Realm the creatures come from. The Aegis is an exception, as it's not fully Hermetic, but for the most part you need spells that drain Infernal creatures specifically, or Wards against Faerie creatures, or general dispels (like Wind of Mundane Silence) against Magic effects.

So, yeah. Trying to dispel formulaically isn't something you'll need to worry about, for sure. It would take way too many seasons to develop a general dispel for all Realms, then a Form-focused dispel for every Form/Ability in every tradition, and... Well, the list goes on.

EDIT: On that note, watch out. PeVi's dispelling ability is actually much less dangerous than the true monster that might be born... Might-draining. Be careful with your creatures.

In the PeVi guideline, under Dispel level of a specific type. There are 2 examples, one is defined as Shamanic control spirit. Which by default mean such spell would be useless to counter a faerie entrancement. But it is true that the base level remain the same.

If you have Legend of Hermes, chapter 2 covers Conciata discovery which was about integretating the four Realm of Magic under Vim. There are virtues to be integrated to make Vim spell easier to use across Realm.

Necrothread! :smiley:.

Would you dispel an ability like entrancement using as level =

  • ability score x5 (like parma magica in wind of mundane silence)
  • ability
  • ease factor used?
  • MAX (ease factor , ability score x5)


It should be "ability score x5 (like parma magica in wind of mundane silence)". See for this HoH:S p.129 The Heathen Witch Reborn, which "can be used as a template for spells that affect other types of exotic magic".


And remember that the easier guideline (like from Unravelling) needs to be specified against a specific Tradition (e.g. Hermetic, Rune magic) as well as a type (corresponding to Hermetic Forms, specific Runes etc.). Check out Errata for GotF for Philipus Niger's spells.
And the harder guideline (like Winds of Mundane Silence) does not.

Yes Christian, I knew this. Thanks for the reminder.

I wanted to be sure what level would my dispel spell need to reach and was of the opinion of Oneshot.