Is there a way to make a spell hard to dispel?

[callen]

While the location of the parentheses is indeed vague in the guideline, it is also addressed in another two spots in core, and there is only one way to reconcile them:

Dispel any magical effect with a level less than or equal to half the (level + 4 magnitudes) of the Vim spell + a stress die (no botch). (guideline)

Let's say you want Wind of Mundane Silence (using this guideline) to dispel a level-X spell. We have:

• Guideline, halving the roll as well: 0.5(spell level + roll) ≥ X. Multiply both sides by 2: spell level + roll ≥ 2X
• Guideline, not halving the roll: 0.5(spell level) + roll ≥ X. Multiply both sides by 2: spell level + 2x roll ≥ 2X

Now look at what the spell says:

You can cancel the effects of any spell if, with this spell, you can double the level of the spell on a stress die + the level of your spell.

There is clearly no 2x the stress die there. This agrees with the first option and disagrees with the second.

And then we can look at either p.156 or the erratum for that page, where we find

a level of up to half (spell level - 5 + stress die).

This is also in agreement with Wind of Mundane Silence and the first reading of the guideline.

Therefore the correct interpretation is that the die roll gets halved in that guideline. Not obvious since you have to look in two of three places, but definitely not open to interpretation.

[ezzelino]

@callen

Therefore the correct interpretation is that the die roll gets halved in that guideline. Not obvious since you have to look in two of three places, but definitely not open to interpretation.

I see. Good to know!
In that case, the apprentice will only have to roll ... 95 or higher on a stress die. She needs to roll four 1s in a row, followed by a 6,7,8,9,0, or by a fifth 1 and any number but 2. So she has a probability of 0.0059% of succeeding, instead of 0.059%.

It will take her 10 times longer, but it's by no means impossible. Instead of having a slightly better than 50% chance of "rolling a dispel" every 2 hours of work, she has it every 20.

If her pater increases the "therapy" to three hours in the morning, and three in the evening, she still has better than a 77% chance of succeeding by the end of the week. Make it eight hours a day for a tenday, and it's better than 96.1%. So the point made by the OP remains valid, in my opinion.

[Red-Shadow-Claws (Itzhak Even)]

And how many Warping points will she get in that time?

[ezzelino]

@Red-Shadow-Claws

And how many Warping points will she get in that time?

Uhm, zero?
Why should she get more?
Unless there's something weird in the cinnamon pastries...

[Red-Shadow-Claws (Itzhak Even)]

Because she's casting hundreds of spells, each has a 1% chance of a botch (with no Aura, roll 10 on the casting, and another 10 on the botch die.) each time she casts the spell. So, her chance of getting a Warping point, is much higher than her chance of successfully dispelling the curse.

1% vs. 0.0048%

[ezzelino]

@Red-Shadow-Claws

Because she's casting hundreds of spells, each has a 1% chance of a botch.

Why? Non-fatiguing spontaneous magic has no chance of botching.
That's why I've argued it's so useful, and losing it to a Minor Flaw harsh.

[Red-Shadow-Claws (Itzhak Even)]

Non-Fatiguing spontaneous magic doesn't get to add a dice roll, so your sample apprentice cannot dispel even a level 1 spell.

[ezzelino]

I think there might be some confusion here.

Non-Fatiguing spontaneous magic indeed does not add a stress die to the casting total. So, yes, the apprentice is casting a Level 2 spell (Base 1 + 1 Touch) over and over. It comes from a casting score of Pe 5+3 + Vi 0 + Sta +2 + Aura 0 = 10, divided by 5 without adding anything because it's non-fatiguing spontaneous magic.

But the PeVi dispel guideline adds a stress die to the (Base 1 + 4 magnitudes) of the spell, before everything is divided by 2 (because it's dispelling unfamiliar magic) and compared to the target spell. And it's a stress die that explicitly cannot botch.

[Istyatur]

To throw more math options, A General Dispel is Generally Useful, and lots of magi have probably need one at various levels and have lab texts in your library. Maybe not at a perfect level for you to cast, but when not under any pressure its a simple die to the casting total, still a 'botchless stress die' to the result. While you can argue that hours upon hours of casting would still be stressful enough to risk a botch (I wouldn't as non-fatiguing spont magic isn't), and you can add qutie a few levels to the roll. or just space it out more.

A few years later and our Lass has passed her gauntlet and is a full Maga, if still wet behind the ears and at the bottom of her Covenent's totem pole.
She had a season to study a primer on Vim (summae lv 5 quality 15. well within limits), to get a Vim art of 5, and improved her Perdo by 2 levels for 7+3 for a Perdo Vim casting score of 17. She couldn't find a lab text for a general dispel of 15, but did find a lab text of general dispel lv 20 (lv 15 + 1 touch).
She has an Int of 1, a Magic Theory of 2 and a lab with a magic aura of 2, just enough to reach the 20 needed to learn the spell. While casting it is a little tricky (requiring 3+ on her roll), a success dispels a (15+20+die)/2 spell. A lesser curse (lv 25) only requires a roll of 15 (3.8%) while a greater curse requires a roll of 65 (0.00269%), or 25768 tries for 50-50. At six seconds a spell, that's 43 hours of casting, or about a week for a 50-50 shot. not great, but hey, beats suffering under the curse forever like a peasant.

While my first example fatiguing spont did neglect the range, it also neglected the stress die which had a decent chance of improving the starting number enough to make up for it, especially since “Most spells are assigned a level, which is usually a multiple of five. It need not be, however, and magi may well invent spells of intermediate levels. Spontaneous spells often have other levels, as well.” And while yes, this does have the chance of botching, it should only be a single botch die which means there is a 1% chance of 1 warping point. A problem for a marathon casting session of thousands, but I also wasn’t thinking of a lv 50 target. And the math for two stress dice is much more complicated. If someone has it somewhere or wants to do it, Id love a copy since I don’t want to do that math, but even lowballing, she likely can dispel a lv 40 effect before she gets a point of warping.

Fortunately, that's secondary. We have already done enough math to to answering the question: RAW, there isn’t a good way to prevent it. No matter what you do, the stress die will eventually explode enough to win.

If you don’t like it, house rule the guidelines to a simple die, limit the explosions, or have the ‘not botches’ do something to penalize the mage. Depending on how hard you want to make it and how much you think magi know about how magic works, penalize them with loss of confidence or say “NO, thats metagaming. You have no way of knowing that it works that way.” Rule it doesn’t work that way and the die roll is the same for a day, or week, season, until they increase their Perdo or Vim. Lots of options for house rules. but RAW, hermetic magic is just really good at getting rid of magic.

However, even RAW you can make it harder. Many thanks to Ezechiel3571’s for pointing me on the right track. I neglected to consider how they would determine the type of magic. Looking at InVim, that is a very significant barrier, as it has a lv 15 (5 + 2 magnitude), neglecting any TDR. Hide it so they need the +4 vision for a LV 35-40 Sight of the Active Magics.

Or, leave it out and mask its aura with a PeVi spell

Gen: Make something (including a magical item) seem non-magical to any Intellego spell of less than or equal to twice the (level + 2 magnitudes) of this spell
At touch +1 and moon +3 a lv 30 spell would block it form detection form lv 40 spells for a month. If you

If your feeling vindictive, add on a CrVi “Create a magical shell which gives false information about the target to Intellego spells with level less than half its (level plus one magnitude).” The half (level +1 mag) means it will only fool apprentices as a normal spell, but as a ritual it can be momentary and last for quite a while. After all, if it looks like a lv 40 MuTe spell it might take quite a while to catch on to why you dispels aren’t touching the wards that have nothing to do with Terram.

Or, and this is probably the intended way, though its horribly unobvious and intuitive to figure out: the Disenchant spell example indicates something that isn’t even listed in the core book. In HoH:TL there are more guidelines that indicates that ‘magical effects’ does not include enchantments. Dispelling an enchantment requires a ritual, which means it costs a lot more time and vis. Its slow, but it works for warding your secrets.

For curses? Homebrew looks to be the only option. Nerf the PeVi guidelines, or nerf stress die (ive seen a house rule where instead of doubling it just adds 10, still repeatable but it takes a lot longer to hit 30s and 40s... and very long time to reach 80s and 90s). Make a new virtue or ability depending on how hard you nerf and how hard you want the curse to be to get rid off.

[Ezechiel3571]

@Istyatur

For curses? Homebrew looks to be the only option.

No necessarily. Knowing what king of magic is at work, is not just knowing "this witch cursed this farmer". My understanding is that the mage must have some basic knowledge of the foreign magic, through appropriate Culture/Area Lore, or what ever skill is the equivalent of MT in this magical practice (Folk magic, for example). This is where Pralixian have a definitive edge versus other Hermetic practitioner, especially when the power comes from a virtue and not part of a "tradition" (in the sens of a group of users using similar techniques and able to teach to each other how to improve their skills).

Without going immediately in the area of house ruling, you can use skill's checks to assert if the mage does have a good enough understanding of the magic he is trying to dispel or not. For example, to affect a Fortunam effect from a Learned Magician should be pretty tricky, since not a single Art comes close to replicate such effect.

[Arthur]

@Istyatur

Depending on how hard you want to make it and how much you think magi know about how magic works, penalize them with loss of confidence or say “NO, thats metagaming.

It's ironic to be accused of metagaming, when running long probability calculations to determine how many hundred (or thousands) of attempts will be required until the dice (a metagaming feature if there was ever one) roll just right to provide a very improbable result, in a game system designed to (imperfectly) model a universe where magic exists.

At a minimum, force the player to roll all those dice by hand. See how well they like it. And I'm pretty sure the rest of the troupe won't be amused either. If the player complains, remind them that rolling the dice is RAW as well.

[Wingsday]

@ezzelino

Oh. So, in your magical battles, you rule that if a Flambeau casts a Pilum of Fire at an enemy and it fails to Penetrate, then every further Pilum will automatically fail to Penetrate that enemy's MR (unless, say, boosted by vis etc.)?

That's definitely an interesting approach. At first sight I do like it.
But I have never, ever seen it in play.

I've used rerolling every cast in combat because there's risk to failure(my fundamental gripe hee) every time. But that is an interesting scheme, like you roll to determine how all the myriad secondary factors (weather, astrological conditions, mental state etc) are effecting your spell casting at a particular moment and stick with that state through a scene? Pretty neat idea

[ezzelino]

@Wingsday

@ezzelino

Oh. So, in your magical battles, you rule that if a Flambeau casts a Pilum of Fire at an enemy and it fails to Penetrate, then every further Pilum will automatically fail to Penetrate that enemy's MR (unless, say, boosted by vis etc.)?

That's definitely an interesting approach. At first sight I do like it.
But I have never, ever seen it in play.

I've used rerolling every cast in combat because there's risk to failure(my fundamental gripe hee) every time.

But, let's say you are looking at a low-level Mastered spell. Demon's Eternal Oblivion would be a good candidate, because you want it low level so it can Penetrate more easily, and of course you want it Mastered. If cast by an adequately experienced magus such a spell would have absolutely no chance of failure or even fatigue (barring exceptional circumstances), so the only question would be whether it does Penetrate. By what you say, if the first casting failed to Penetrate, you'd stop checking for Penetration by the Let It Ride rule?

[ezzelino]

@Arthur

It's ironic to be accused of metagaming, when running long probability calculations to determine how many hundred (or thousands) of attempts will be required until
...
At a minimum, force the player to roll all those dice by hand.

I would stress that no one here is saying: because the RAW make dispelling easy if a magus has ample time, then setting-wise dispelling IS easy. I think that the main point behind the OP instead is: the RAW makes dispelling too easy compared to how it should be within the setting, in the niche case of having a few days to work on the dispel.

There are two possible solutions. First, the troupe decides that the RAW do not apply to that niche case (a process that, in some troupes, involves the SG "warning" or "punishing" players). Second, it's an interesting challenge to see if the RAW provide some means for a magus to protect his spells from a would-be dispeller of little talent but ample patience. The OP was about the latter.

As for me, I fail to see anything passive working (except, perhaps, hiding/deception). The best I can fathom is a magical "alarm" that summons countermeasures. I would point out that in the real world it's the same: virtually no safe is proof against thieves who can spend a few days working on it in peace.

[Wingsday]

No, I've done rolling every time in combat so far, again, there's risk in failure ie the demon gets to attack you or whatever, probably if the maga can cast and penetrate every time regardless of dice rolls I guess wouldnt require them to roll, but i also dont know if id run this encounter on purpose that often

[temprobe]

@ezzelino

And it's a stress die that explicitly cannot botch.

I'm tempted to say the obvious fix is to tie the die roll result to the spellcasting roll result.

[Arthur]

Or eliminate it alltogether. Rego-based Vim effects (suppression or sustaining) don't involve a die roll.

Or reverse it. Add 1 more magnitude to the formula, but have the targeted spell(s) roll a resistance against the dispelling effect.

Or make it a simple die.

Many ways to close the loophole.

[RafaelB (Rafael Bessoni)]

A bit late for the discussion, but if there's nothing preventing the character to retry an action then the logical outcome is that the character keeps trying until she succeeds. While magi don't have our modern knowledge of probability and statistics, they would know that even the weakest dispel has a low chance of unraveling strong magic.

Someone mentioned the "Let it Roll" rule. I genuinelly think it's one of the worst game mechanics ever, because it imposes an arbitrary limit to the gameplay (no, you can only try this once. Why? No real reason. Just because). I usually go with the following adjudication proccess:

• Can the action succeed? If not, then it automatically fails. No use to roll. If this is something the character should know, the player gets a clear indication of that ("you can't jump over an 1km chasm, not even with an 100000 on the die and your character would know this action has no chance of success. Do you really want to try?")
• Can the action reasonably fail? If not, then it automatically succeeds. No need to roll. "No, I won't require a 'walking' roll for you to cross the bridge, you literally can't fail that in this case."
• Is there a cost to the action that prevents it from being repeated? If not, assume the action succeeds eventually. No need to roll. Note that generally speaking, time alone is not a cost.
• If neither failure or success is guaranteed and the action has a cost, then, and only then, a roll should be requested.

One of the positive aspects of Ars Magica is that magic has, generally speaking, zero cost. No mana, no spell slots, no limits to casting - as long as you can do it under controlled conditions. Non-fatiguing spont spells are the epithome of that. If something can be done through non-fatiguing spont spells as long as you cast several times, then one should assume success after an appropriate amount of time passes and move on, as appropriate.

On the example put forward by ezzelino (with the apprentice trying to dispel a curse) one might at most request the player to make Stamina rolls to avoid long-term fatigue for the repetitive action (which is very reasonable IMO) every... idk, 4 hours? 8 hours? and roll once to see if you manage to dispel the curse on that time frame. The cost of the action becomes the time it will take your to succeed (or the patience of the cursed noble in this particular example, who needs to work and do other things, and does not really have the time to tag around you for days w/o end).

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IMO the problem here is with dispelling itself and it's inclusion of a stress die on the guideline. Making it a simple is the most elegant solution IMO. It still leaves a bit of chance (which means you can have nice, exciting moments like a magus trying to dispel the wall of fire over a few rounds while the grogs hold back the giant) w/o making dispelling trivial for anyone with enough time on their hands.

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As for an answer to the original question, change the cost. If dispelling itself has no/low cost, make so that staying around for a long period of time has (unconfortable area, presence of beasts, patrolling guards, etc). Make the area physically or logistically difficult to access, so that the magus wanting to dispel the effect will not arrive in his best condition. In summary, if succeeding is possible with enough tries, make trying itself costly.

On the field of house rules, besides changing the dispelling guidelines, you could mess with spell mastery. There are masteries which make your PeVi spells better. You could invent a mastery to make mastered spells harder to dispel (on the assumption that we are talking about a formulaic ward, of course).

Otherwise, it's as said by ezzelino: no safe is proof against a thieve who has the time and resources to work in peace.

[Wingsday]

You're welcome to sit and watch someone else roll dice for half an hour, not really my idea of a good time

[RafaelB (Rafael Bessoni)]

Not what I suggested at all.

EDIT: But I did forget a bullet (which is implied on the rest of the post) which I'm editing to add right now.