Wandering Aegisessesess

Aeges? Aegides?

Anyway, a lot of people would like wards to move. There has been a basic assumption in ArM5 that Aegis, in particular, does not, but that assumption has not surfaced explicitly in many places, and so it might be possible to change it.

LoH would need errata.

Northern Seas, in Through the Aegis, does not have an Aegis, but it is a Spring covenant, and I didn't find an explicit declaration that it couldn't have one when I looked through. They do have a Lab Text for it, but no Casting Tablet, and no-one knows the spell. ("Aegis" appears on every single page in that book, so I may have overlooked it. "Hearth" helped, but I might have missed a simple reference to "Aegis".)

I also have a single PDF file with all of ArM5 in it. It is 5,895 pages long. So, I'm going to crowdsource (aka asking you to work for me for free). Is there anywhere else that we explicitly said Aegis was immobile?

And, related, what can people come up with that breaks horribly if Aegis is mobile?


The Box "A Note on Boundaries" on page 123 of LoH?

That's the bit of LoH that would need errata.

I don't think it breaks anything horribly, but you would want to define what happens if one Aegis moves across another. Possibilities include:

  1. The moving Aegis compares its Penetration to the stationary Aegis' level and either penetrates or fizzles. (Probably current RAW.)
  2. Both Aegises compare Penetration and the lower one fizzles.
  3. Both Aegises remain in effect, as if they had successfully been cast separately on overlapping and/or concentric Boundaries; magi of either covenant will have a casting penalty within the area of overlap, unless they get an invite and casting token from their counterpart. (My preferred interpretation.)

I always thought, that at least the editor and many authors were aware of the potentially devastating use of movable Aegides in assaults - and when it came up in LoH acted decisively, without spelling out the problem.

Anyway, here's a short summary of it.

A movable Boundary can be anything, from a ring of rope to more stiff light metal rings - may be even kept rigid by magic. It all depends on the house rule on boundariness to be kept if the Aegis cast with this boundary moves. Such an Aegis of assault can by magic be moved fast and silent, even teleported in an instant, turned invisible and protected against many kinds of detection, mundane and magical. The magi protected by it can then slap it - in a single round, if needed - around any reasonable area with inhabitants, traps or magical threats they wish to eliminate or subdue, benefiting from its all-around protection.

So this changes many published adventures, and many sagas, significantly.

An adequate variant ArM5 p.161 Unravelling the Fabric of (Vis) can be easily put into a high penetration lesser enchantment (the Wand of assault) able to easily bring down an Aegis in a round as well.

Wand of assault and Aegis of assault together can replace the Aegis of any covenant in two rounds by one protecting the attackers, not the defenders. So they reduce every covenant remotely threatened by devious sodales into US aircraft carriers in the south china sea: on constant high alert!

They have to anticipate an extremely fast attack they can only prevent, if everybody is always on the magical lookout, detects the invisible Aegis of assault in time to bring its own Wands of assault to bear before it lands. No study, no experimentation, no recuperation: just alert!

Doesn't look like Ars Magica to me. :exploding_head:

Here still a poem on the subject by Christian Morgenstern, 1911 - in German:

Laß sie Dreadnoughts bauen und aber Dreadnoughts
und vom Luftschiffkreuzer das Heil erwarten!
Unerträglich würden auf Erden sonst die
Tage des Glückes.
Alles lebt in dulci jubilo, nirgends
haust die Pest, der Hunger, die Not, die Sorge.
Singend gehn die Völker zu Bett, und singend
gehn sie zum Frühstück.
Müssen Patrioten da nicht zu Werken
kriegerischer Gewalt zusammentreten
und dem kannibalischen Wohl der Völker
Schropfköpfe setzen?
Laß sie Dreadnoughts bauen und aber Dreadnoughts
und vom Luftschiffkreuzer das Heil erwarten!
Unerträglich würden auf Erden sonst die
Tage des Glückes.

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That is an evil tactic.
I would counter it with the following ruling:

If you move just the boundary marker through the air or by teleport, then during transit it is not a boundary of anything in particular - and thus not a boundary for those moments of time, causing any T: Boundary spells targeting it to fail.
(Dragging it along the ground would theoretically work, since it will always be the boundary of something then. There are obvious practical problems with this approach though unless you are within a large open area all the time.)

This unlike, say, a flying castle. There the boundary of the castle remains a boundary even if the castle moves.

In other words, a movable Boundary would only work if you also move that which it is a boundary of.

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You need to be a lot more precise here: isn't it the air it bounds during that time of flight. And if it teleports, just when does it bound nothing? There is no time span while it teleports.

In brief: it is difficult to resolve a problem just discovered with a quick fix. I had the impression, that editor and authors thought through their fix of LoH p.123 box.

Am away from my books, but I was under the impression that dispelling a ritual spell, requires a ritual dispel.

In am not aware of


I think this issue hasn't changed. We are discussing here changes in the rules - so must absolutely avoid house rules.

While it might not need a ritual always, I'd consider covenants like Durenmar and such to have high-level Aegis, so it's likely that due to the level needed to dispel them, it would become a ritual spell.

Sure, a spring covenant that is newly created isn't likely to have a powerful Aegis, but the established summer and autumn covenants? Yeah.

Reread ArM5 p.96:

The exception is spells that are Rituals only because the spell level is over 50, not because of Duration, Target or major effect, may be placed in items.

This also applies to variants of ArM5 p.161 Unravelling the Fabric of (Form) in items, and ArM5 p.99 Effect Modifications for high Penetration.

We are discussing a big rules change here. Please take it seriously.

This is a really gamey way to read the description of a boundary as it is in the ArM5 rulebook. It is true that the rules dont expressly prohibit it, but it is certainly not how I would read a boundary. I think a more reasonable interpretation of what is written is that the boundary needs to include its contents at the time of casting.

That is you cannot make something which is the boundary of nothing, and then move it around. You could use a city wall as the boundary to target the walled area, but you cannot build a wall in nowhere, move it to a new place and then affects the new area that it encircles.

Additionally your problematization seems to rely on an assumption that people will play ars magic like it is a tactical board game.
I have no doubt that if a group playing in ars magica wanted to they could create characters able to enchant stiff ropes with ultra invisibility and make ultra high-level ultra high penetration wands with Unravelling the fabric of Vim, and still also have combat potential.
But the game setting does very little to imply that such magi are common, even if a dedicated wargamer could create them using the character creation system. There is also very little in the setting to indicate that groups of magi that are even willing to attack each other in this manner are common.

In other words even If what you describe is technically possible, which I admit it kinda is, I dont think it represents a threat to the game.

Groups that want to play like this already can, and trying to make the system "power-gaming proof" is a fruitless endeavor. Groups that previously would not tolerate such nonsense, wont even under the proposed change to the rules.


It is nearly always the boundary of the air within it - unless you imagine to operate outside of the lunar sphere.

No. I assume that Ars players don't want to play it that way - so giving strong incentivation to do it anyway is making Ars Magica into the wrong type of game for them and me. And doing so with an inconsiderate rules change 17 years after it started is quite inexcusable.

I consider this unneeded rules change a serious threat. There are always "clever" gamers, who also often appear on this forum, can make use of such exploits and destroy a saga or two - and thus losing players to ArM5.
That was also the reason, why I kept mum about this potential exploit before @David_Chart set up this thread and it became suddenly a verrry real possibility.

Oh yeah - he at least guessed such an exploit. See in the OP:

First, I don't know what makes you think I do not take this seriously, and frankly, I don't care. I do take things seriously, especially when it comes to games I like.
Second, my comment was never that you cannot place such an effect in an item, though a reading of this section can change your mind:

Core p. 157
Spells and magical effects do not have sizes, so size modifications do not apply to the levels of Individual Target Vim spells. However, Vim spells affecting areas, or number of spells, must be increased in level for large areas or large numbers, as normal.

My reading of this is that Unravelling the Fabric of Vim to affect an Aegis, which is a Boundary spell, wouldn't be an Individual target, but should likely be a boundary, or at least, have some Size modifiers.
This could well impact, not just whether it can be placed in an item, but also, how many extra levels you need to add to the effect to make it able to dispel an Aegis. Even if it stays non-ritual, with the extra Sizes it could very well be a level 90+ effect to be invested, which would require a very dedicated Magi to be able to even attempt this, and one who might have close scrutiny by quaesitors due to the nature of such an item. (And of course it still all depends on whether the Troupe will agree to it)

But if we're being serious, I don't think enchanting a ring of rope with Aegis should work, unless you've embedded said ring in the ground. And then, you need to move, not just the ring, but the entire piece of land it's in, to not make it fizzle. That would be my ruling as a SG, and I think most troupes would agree.

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No. Common misconception. That's for Items.

Got that. Always good to learn.

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Then reread your own quote from ArM5 p.157:

AotH is a spell, hence it has no size! Hence affecting it with UtFo(F) does not require size modifiers to the Target.

UtFo(F) does not do that. It "cancels the effect of any one spell ...", which is also stressed by its T: Ind.

Auram spells usually affect air as phenomena (winds, odors)
rather than as gases (a modern concept)."

"The empty air?" Points at the middle of the ring floating in the air "But there is nothing there?"

More seriously, while I certainly see how one can consider the thin disc of air inside the boundary to be what is bounded, I wouldn't allow that as a boundary in my game - it is too contrived and artificial. It is not what I would intuitively consider a boundary of something.

As for teleports not taking any time. Are you sure of that? They don't take even an instant?
Some teleport spells are described as "Instant", but every action in the real world that is ever described as "instant" or "instantaneous" actually takes some time, however short. I see no reason to believe the rules use the word differently than elsewhere.


I did handle both teleport and flight of an Aegis Boundary - just to be on the safe side. This is, because TME p.106 box Optional Rule: Limits on Instant Transportation allows sagas to have teleport "reconfigured as traveling in the blink of an eye" to slow it down to just "flying exceptionally fast". That blink of an eye in the bible is the smallest unit of time. But without that optional rule, the teleport is instant transportation.
AFAICS this distinction is not very important for my example.