This apparently came up 12 years ago, but is not as clear as it could be.
Simple case: I am casting a spell with a Group Target. There are four magi in the group. (I am living really dangerously.) I am casting the spell at Voice Range, so I do not need an AC for targeting.
I have an AC to magus A, and various sympathetic connections. I get a huge Penetration bonus against him, and he is toast.
I have an AC to maga B, but no sympathetic connections. I get a decent Penetration bonus against her. Maybe I will get lucky.
I have no AC to magus C. He will be fine.
I think I have an AC to maga D. However, I am wrong, and I actually have an AC to maga D's identical twin, who serves as a decoy for her. She will be fine.
I think that this is obviously how the rules are supposed to work, and that this also applies to all the container targets (Circle, Room, Structure, Boundary).
I also think that an AC to the structure (for example) itself will not increase your Penetration against other targets within the structure.
Do people agree? If so, I will try to add a small erratum to make this explicit.
That is a perfectly reasonable way of treating things, but I do not think it is obvious at all that is how the rules are supposed to work.
On the contrary, my conclusion, based on how p82 in the core book talks about "the penetration total", was that a given spell only has one penetration total which is the same for all targets.
It is also not at all clear that it is possible to use more than one AC at a time, especially since p84 says that "Only one Arcane Connection can be used to give a bonus to penetration."
This can be read as only one AC per target, but can also be read as only one AC per casting.
This brings to mind a similar situation, when can an ongoing effect can have a Penetration Bonus from an Arcane Connection against individuals that weren't effected at the start of the spell? For example:
I'm casting a R: Touch, D: Diam, T: Room spell, no AC needed for targeting. Type 2 Container
I have an AC to Magus A, who is in the room when I cast the spell.
I have an AC to Magus B, who is outside the room when I cast the spell.
I lack an AC to Magus C, who is in the room when I cast the spell.
I lack an AC to Magus D, who is outside the room when I cast the spell.
Who does the spell have Penetration bonuses against?
What if I pluck a hair from Magus C or D's head after casting the spell, can I gain the Penetration bonus now?
Magus B presumably impacts stuff like Pilium of Fire, The Crystal Dart, basically any non-aimed spell where the intended target differs from the Target, attacks while under shapeshifting spells, Mutoed poison intended for a particular Magi...
but the Ring/Circle Magic virtue in HoH: Societates would seem to imply that either none of these would gain penetration bonuses from ACs against their targets, or that Touch/Ring/Circle spells are an exception to the general rules regarding penetration bonuses from ACs.
So, something about Penetration has been bothering / confusing me for a while now, this seems as good a place as any to ask;
Say that we are casting a spell akin to either personalized Shape of Woodland Prowler or a Blade of Virulent Flame. Now, if you wanted to make sure either one of these would have sufficient penetration to affect most things...what AC do you use?
Do you use the AC to the sword (BoVF case) or to...yourself as the caster (SoWP case)...or to whatever target you want to flaming sword / wolf to hit? In the former case, I assume it should be viable to use your own blood to bolster the Penetration of the spell, but is this Penetration Total than compared to the MR of whatever you strike from then on, since the spell effect took hold more strongly on the sword / yourself (in case of the wolf spell)?
Or if its the latter case, would it mean that such spells technically have 2 separate Penetration Totals (1 vs. source of AC used & 1 vs. everything else?)
I think it's vitally important to pay close attention to HoH:S p.102 here (as ArKhaic points out):
Since in most cases Hermetic wards do not actually target the creatures affected by them, most magi cannot boost their Penetration Total with an Arcane Connection to a supernatural being, unless that being is inside the circle when the ward is cast.
If all of Hermetic magic functioned otherwise, then it wouldn't make sense to have this one narrow gap on what is actually a broader incorporation (affecting unpresent things). Meanwhile, this is how the Hermetic wards work without having incorporated special Columbae individualization/penetration stuff. So the rules here should generally hold. What I see from here:
You should not be able to, for example, use and AC to yourself when you MuCo(An) to help penetrate someone else when you bite them. I expect most people would probably rule this way, and it is consistent. This doesn't immediately pertain to David's question, but it does matter for Kodlak's follow-up.
Look at what happens with the target that is present, though. You can use a ward against a particular supernatural inside a circle to trap it there and gain a bonus for the AC, even though this ward will work against other beings as well, perhaps also keeping them penned in. So we already have a scenario where the AC provides a penetration multiplier for some but not all of those affected.
To avoid further wrinkles, the AC's to magi A-D in David's Group should provide different penetrations against individual magi in that group. So David's "obviously how the rules are supposed to work" is consistent with HoH:S.
As for an AC to the structure, if an AC to the structure works (which could affect beings who hadn't been present), why would we not be able to use an AC to the material a circle is drawn on to boost? If we can, the ward stuff becomes fairly nonsensical, so it seems we cannot. If we cannot with circular wards, which are supposed to be more effective against unpresent targets, why should we be allowed to with Structure. And if the AC to the Structure doesn't work against unpresent targets, why against present ones? And if it does work with present ones, why would you even need an AC to a present supernatural being with the circular ward? So it seems like David's choice that the AC to the structure doesn't apply to others inside it most consistent here as well.
Now, all of that is based on consistency with the only place I know of this showing up. ErikT is correct about this not being obvious from the core book. The core book does use singular, implying there is only one penetration total. While it talks about penetrating differently, this is all based around the targets having different Magic Resistance. Meanwhile the core book does say you can only use one AC, and ErikT is correct that it's not clear this would be by target rather than by casting.
The AC is supposed to be to the "target," not the "Target," right? For example, you don't use some AC to a nonexistent fire to get your PoF to penetrate against your opponent, you use an AC to the opponent. The opponent is the "target," while the fire is the "Target." So let's say you're casting a ReMe Structure spell to put the people inside to sleep. Then the people are the "targets" while the structure is the "Target." For consistency an AC to the structure would not be what is used to penetrate against the people here.
Thinking on it, I am not so fond of the idea of being able to use multiple ACs for a single spell.
Doing that, one quickly runs into several questions and potential abuses.
Does one need to hold each AC in your hands to use them?
Do you need to know an AC is an AC to one of your targets to get the bonus from it?
How many AC can one potentially make use of at one time?
I am thinking of someone holding a bundle of hairs from all individuals he dislike that he has been able to get a straw of hair from (each straw of hair thus being an AC to the person it came from), using that bundle of ACs every time he casts a spell just in case one of the targets happen to be one he has an AC to.
I am not liking the idea that someone could do that - it seems both silly and munchkiny.
The solution seems to be to either create a bunch of detailed rules about usage of ACs, or restrict it to using at most one AC per spell.
I think most of us have been assuming you could only use one AC at a time anyway, but I could clearly be wrong about that.
One thing to keep in mind if you can use several ACs per spell is weather you can use this to target AC range group target spells
Personally i think this is pretty cool, and also requires 6 magnitudes(enough to make a base 4 spell cause warping with no duration adjustment) so I'd be inclined to include it
I have no reason to disagree, but I could get behind the "one AC per casting".
I don't see how that limitation is anything more than an interesting complication.
It makes sense to target a magus and his grogs with T:Group. Since only one target has MR, you only need an AC to that target. Enough to cancel the T:Group magnitudes if you plan well.
Quite. But be honest: do we really need more complications in ArM5?
Wouldn't keeping such a bundle viable be an enormous sink of lab seasons? Or require lots of apprentices to work for you, whom you typically need to instruct as well?
Regarding handling multiple ACs to affect multiple targets could be common enough to be worth clarifying. Can a mage handle one AC per Penetration skill level ? Is it linked to MT or Concentration ? Or Finesse (my least favoured option since it gives another use for Finesse which does not really need that, even if it is one of my favorite skill).
By the way, I don't like the idea of a mage grabbing a handful of AC "just in case". I find that the act of magic is deliberate and each casting, even formulaic is slightly tailored to the specific situation the spell is casted for. So the "grab ACs, just in case" sounds like random spraying the area to see who has RM, who is my enemies and who is innocent bystanders. However, beside my own preferences, no rules prevent from doing it, so I could leave without clarification and just house rule it.
There is another case where handling two AC would be needed (If the community find it too niche, then drop it), consider the situation:
There are several guidelines where an AC is part of the guideline, without being the target/Target (for example: ReCo and ReTe instant movement spells).
So in this case, the mage needs to have an AC for the spell to resolve, towards the landing spot of the spell, but if he is affecting a target with MR, he would benefit from another AC. In this case, each AC fulfill a very different role, how does a mage physically handle the ACs in this situation ?
I could see him holding in each hand one AC and during the casting of the spell referring to each of them. But it is one more case needing clarification on how many AC can a mage handle properly.
maybe a penalty for trying to use an inappropriate AC? Maybe it degrades faster or becomes un-fixed?
I have this image of a world where magi don't spend seasons fixing ACs but instead hire hordes of thieves to steal the hair from their enemies and victims on a regular basis...
I don’t see a problem with a spell being cast with a handful of AC.
Both for a T: Group spell cast against several different people. Or for a multi cast spell against several different targets.
Even without ACs you could have different Penetration totals, if some of the targets were affected by a Focus (eg women) and some weren’t.
Penetration (p. 84): Replace the section with the following text.
Penetration
Penetration is the ability of a spell or other magical ability to get through any Magic Resistance that the target might have. If the target has no Magic Resistance, Penetration is irrelevant. A single spell may have several targets, for example all the members of a Group. In that case, any targets without Magic Resistance are affected no matter what the Penetration of the spell, but a targets with Magic Resistance are only affected if the spell Penetrates that target's Magic Resistance.
Any character with the Penetration Ability can use sympathetic magic to increase the Penetration of her magic against a particular target. The Penetration Bonus starts at one times the character's Penetration Ability, and the multiplier can be increased. This requires that the character have an Arcane Connection to the target of the magic.
[Bonus Table Unchanged]
The same Arcane Connection can be used to both allow the use of Arcane Connection Range, and to boost Penetration. Only one Arcane Connection can be used to give a bonus to Penetration against a single target, but it is possible to use Arcane Connections to multiple targets to boost the Penetration of a single spell. The spell might then have a different Penetration against each of its targets. The maximum number of Arcane Connections that a caster can use in single casting is equal to her Penetration Ability score. Note that a caster might think she has an Arcane Connection to a target, but be mistaken. In that case, the Arcane Connection counts against the maximum she can use, and does "work", but the increased Penetration is irrelevant as that individual is not targeted by the spell.
Once a character has an Arcane Connection she can use other sympathetic magic to increase the multiplier further. Any number of sympathetic connections may be used, and their bonuses stack. The nearby table provides some examples, but is not exhaustive. Each troupe should specify the kinds of sympathetic connection it allows, but no single connection should give a bonus of greater than +2.
I think there should also be some small note on p82 "Penetration Total" to indicate that it is possible to have different Penetration Totals against different targets.
The wording
it is possible to use Arcane Connections to multiple targets to boost the Penetration of a single spell.
The spell might then have a different Penetration against each of its targets.
in the suggested change seems to imply that having different Penetration against each target only happens when you are using multiple ACs, which I am sure was not the intention.
Perhaps rephrase that second sentence to something like "So when there are multiple targets, it is possible to have a different Penetration against each of them" ?
I mostly really like this. I would change "but a targets" to "but targets" near the end of the first paragraph.
The one thing that could be really improved is the first sentence of the first paragraph. Penetration isn't just to get through Magic Resistance of a target, though it mostly is. There are also other scenarios. For example, I MuCo(An) into a wolf and several hours later across Europe I bit someone. I still have to penetrate with that bite, even though that person really isn't a target of the effect and shouldn't be warped by it. There can also be lack of clarity with things like BoAF. The Target is the fire, but the target is the person you're placing the fire on.
Bob is correct about the minimum number of AC's. I don't mind the minimum being zero, but I could also see the minimum being one. I do like that having a braid of a thousand hairs, each from a different person, doesn't work.