How does the Aegis work

Games Discussion Ars Magica
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There is too much going on here for me to keep track of something that in general I mostly look at as "simply working" so yeah, I look forward to your accumulated post so I can get a "this is what is going on" element.

Basically, for me, Aegis is 'safe' to cast (meaning for the most part automatic for covenants), can be changed in size with no breakthroughs (so covenant sizes aren't limited), don't need to penetrate (meaning Might level is what it protects against), doesn't harm a magus (by stripping longevity from them or destroying familiar bonds) and such. Outside to inside is near perfect, within to within can be interesting.

Anyway, as I said, I look forward to seeing a more accumulated text.

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Not current canon but:

To make longevity rituals, familiar bonds, talisman attunements etc. unaffected by the Aegis without making them explicit exceptions, would excluding permanent effects / enchantments from the impact of the Aegis work? I'm pretty sure there are going to be some unwanted side-effects, but how bad are they?

(Obviously you then need to define "permanent" in a way that includes longevity rituals.)

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Familiar bonds and talisman attunements are exceptional rituals that could be assumed to touch on the limit of the soul- binding something to a magus at the soul level. If a longevity ritual was also within this limitation then the whole framework would make sense again aside from these three things being explicit exceptions to the limit of the soul (presumably a bjorner's heartbeast would be similarly an effect which connects to the soul, which explains a lot about how it is different from other forms of shapechanging)

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On the subject of Hermetic Limits...how does the Aegis interact with the Limit of True Feeling for the Familiar bond (and the associated True Friend virtue you get as a result of the bond)?

Of course, the Cutting the Cords ritual does exist (HoH: TL, pg 75), which short of that being errated means that Hermetic magic can sever a familiar bond, so it being suppressed in some way isn't ridiculous. It's a specific ritual which requires the active co-operation of the bound magus, however.

Edit: Aside from the implications of True Friend for the bond itself, does it provide a convenient justification for not faffing around trying to work out how your snake familiar is going to carry an Aegis token? Just say that the magus has an invitation and True Friend means than the familiar can follow them in?

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If a spirit can be invited in, “given” a token which the inviting magus holds I see no reason a snake familiar (or anyone without pockets) needs to hold the token on them at all times. This spirit thing, explicitly mentioned in the Spirit Familiar text in Mysteries IIRC, implies the token is part of an invitation ritual but holds no actual power related to the invitation beyond that.

I would definitely not consider the true love or friend of a magus invited in if the magus is invited unless said true friend was explicitly invited in as well. If this is the case with a human true friend why would inviting the magus provide an automatic invitation to a familiar based on the same virtue?

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Fair enough, I had forgotten that.

Human true loves/friends aren't physcially barred by an Aegis in the way a familiar with Might is, though. I can see a situation in which someone with a supernatural power (say, enchanting music) is able to pierce the stifling effects of the Aegis to use their magics to melt the heart of the evil wizard and rescue their imprisoned True Love.

Thinking about it further, though, it does make sense that the familiar wouldn't have carte blanche to use their powers without an invitation - yes they may not be able to be magically separated from their magus, but that doesn't mean they can use their magical powers to beg food from the cook whenever they want to.

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There is also a difference for this issue between a familiar with might and one without.

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How can a familiar not have Might?

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A familiar can be a mundane animal- core book p 103 and 104- a familiar is a beast... likely to have a might score.

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Here is an attempt at a clear version of the current Aegis of the Hearth. This is supposed to make explicit that it does not only affect magi, and that it affects all supernatural effects coming in, but it is not supposed to change anything. However, the ambiguity of the published version means that it may well change things for individual sagas.

Comments welcome.

Aegis of the Hearth
R: Touch, D: Year, T: Bound, Ritual

This ritual protects a covenant in a way similar to the way in which a Parma Magica protects a magus. It provides very strong protection against supernatural effects and creatures that originate from outside the boundary of the Aegis, and much weaker and less consistent protection against supernatural effects originating within the Aegis. The ritual also allows certain individuals to be excluded from the effects of the Aegis, so that it does not hinder their supernatural powers at all. These individuals are referred to as "natives" of the Aegis in this description, and other individuals, and the effects they create, are referred to as "foreign".

No foreign supernatural creature with Might, of any type, can cross the boundary of the Aegis unless its Might exceeds the level of the Aegis. The Aegis of the Hearth must Penetrate the creature's Magic Resistance in order to have this effect. A foreign supernatural creature that is within the Aegis when it is created is not expelled, although it does suffer the limits to its powers described later. If the creature were to leave the Aegis, it would need to have a higher Might than the Aegis, or resist the Aegis, in order to enter again. A spirit with Might that is capable of possessing another creature may enter the Aegis inside that creature, as long as it remains entirely passive. It is aware of what is going on, but cannot act in any way, including to end the possession. If the vessel becomes a native of the Aegis, the possessing spirit also does. The spirit can, however, have its invitation revoked (see later) separately from that of its vessel, if the person revoking the invitation knows that the spirit is there.

Any foreign supernatural effect that originates from outside the Aegis and would affect anything inside the Aegis must Penetrate a Magic Resistance equal to the level of the Aegis of the Hearth to take effect. If it fails to Penetrate, the effect fails completely and harmlessly. This applies to all effects, including Intellego effects that would not normally be blocked by Magic Resistance, and effects that would move something across the boundary of the Aegis.

This also applies to an existing foreign supernatural effect that tries to cross the boundary. If the effect cannot Penetrate the Aegis, it is dispelled. However, if the spell is cast on someone with Magic Resistance, for example an invisibility spell on a magus, then the Aegis must Penetrate the magus's Magic Resistance in order to dispel the effect. This includes such effects as the Parma Magica, Hermetic Longevity Rituals, Familiar Bonds, and Talisman Bonds. However, the last three of these are automatically sustained by the underlying magic, and so immediately come back into effect once the magus has entered the Aegis. Parma Magica must be raised again, in the normal way.

Any foreign supernatural effect originating within the boundary of the Aegis must subtract half the level of the Aegis from any Casting Total or equivalent. If the effect does not have a Casting Total, as for an effect from an enchanted item, then half the level of the Aegis is subtracted from its Penetration. If the effect has neither a Casting Total nor a Penetration, like the Parma Magica, it is not hindered by the Aegis once it is inside. This also applies to the supernatural powers of creatures with Might that have been able to enter the Aegis.

Anyone who participated in the ritual to cast the Aegis is a native of that Aegis. Entirely mundane people can participate in the Aegis ritual. At most covenants, only the magi participate in the ritual, to avoid the risk of making disguised demons into natives of the Aegis, but this is a custom rather than a feature of the ritual.

Any participant who has The Gift and has been opened to the Hermetic Arts can invite other individuals into the Aegis. This involves giving the individual a token that was designated as part of the ritual. Individuals that are invited in this way become natives of the Aegis, but they are not able to invite other people in turn. Anyone who can invite someone into the Aegis can also revoke an invitation, whether issued by themselves or by someone else. They do not need to retrieve the token in order to do this. Invitations and revocations can only be issued to specific individuals — it is not possible to revoke "all invitations", for example. Invitations and revocations are effective even if the participant is mistaken about the identity of the individual. A participant can attempt to revoke an invitation even is they do not know for sure that a particular individual has been invited into the Aegis. If they were, then the invitation is revoked, but if they were not, this obviously has no effect. A creature with Might whose invitation is withdrawn is affected in the same way as a creature with Might who was within the Aegis when it was created. Individuals who participated in the ritual cannot be cast out of the ritual; they are native until the Aegis expires, or is replaced with a new one in which they did not participate.

Enchanted items can also be native to the Aegis. There are three main classes. The first is items that were within the Aegis at the time it was raised. Unlike creatures with Might, non-sentient items become native to the Aegis simply by being present. The second class is items created within the Aegis by someone native to the Aegis. The third is items directly activated by a native of the Aegis. Covenfolk who will use enchanted items may, therefore, participate in the Aegis ritual, but many enchanted items do not need Penetration, and thus can be used within the Aegis without any problems. The set of native items, like the set of native people, resets every time the Aegis is recast. Items, however, cannot be invited in to the Aegis.

The Aegis is often cast on the Winter Solstice, as the Magic aura may be slightly higher, and this gives it a full year of duration. It is common for the covenant to hold a celebration for all the covenfolk, and a full council meeting for the magi, immediately after the Aegis is cast.

Aegis of the Hearth was created by Notatus, the first Primus of House Bonisagus. It was a major breakthrough, incorporating Mercurian rituals as well as Hermetic theory, and was the reason Notatus was chosen to succeed Bonisagus. As a result, the spell is more powerful than it ought to be, and has no Perdo requisite. By 1220, Notatus's discoveries have spread, and any magus in the Order is capable of inventing versions of the Aegis with the above parameters. but different levels or sizes. Inventing a version with different parameters, however, would require at least a minor breakthrough, and years of research.

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235

One issue- if an entity within the boundary who does not participate in the ritual is considered foreign, the greatly weakens the monster hook from covenants.

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Wait, I thought if a monster was in the covenant when an Aegis is cast is is considered native. Which is why things like "a hidden dragon in the mountain' is such an interesting plot hook.

PS. Oh, I see silveroak had the same thought. Funny enough I noticed it after I commented myself.

--

As another note, so the Aegis has to penetrate to stop someone rather than having that someone penetrate the Aegis?

Honestly, this seems to complicated and wordy. I don't really thing an essay rather than there just being a paragraph or two helps matters.

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I like the new wording.

Regarding the monster hook, if the creature is either sufficiently powerful, or if the threat is not from Powers but natural attacks etc. It can still be a threat

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"Replacing" an Aegis might better be reworded, or needs explanation. Just deleting ", or is replaced with a new one in which they did not participate" might be best.

Casting a new Aegis onto a site, where there is an old one already, will cause the two Aegides to interact.

Typically both were cast by the same magi, hence the old one does not hinder the new one being set up. The new one will not "replace" the old one, though, before the old one expires.
As written it will not take over invitations into the old one, and will make eventually other items native "by being present".

If a new Aegis is cast onto a site by persons not native to the previous Aegis, the old Aegis resists as described and must be penetrated. But even if successfully cast, the new Aegis does so far not dispel the old one, and hence does not "replace" it either.

EDIT: A minor tricky issue is, whether a new Aegis cast by several magi using Day of Communion, some of whom are native and some are foreign to the old Aegis, is resisted by the old Aegis and must penetrate it.
But it should depend on the main caster of the new ritual, and whether she is native or foreign to the old Aegis.

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In the current rules a being has to participate in the ritual, not simply be somewhere within the Boundary. Being somewhere within the Boundary works for magical items. Being in the Boundary doesn't expel the monster, just reduces its penetration. So this isn't a change.

Unless I misread this, that is to dispel effects already on a being entering the Aegis. The Aegis would have to beat the being's MR to dispel those effects. But if a being fires off an effect from outside the Aegis at someone inside the Aegis, the effect must penetrate the Aegis. This adds clarity of which penetration direction is needed for existing effects on a being entering the Boundary, as that had been unclear.

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I like it. A lot.
Minor criticisms:

  1. I dislike the "native but can't invite" phrasing. I'd prefer a third classification: Invitee. Cannot invite but their powers are unaffected by the Aegis. This is essentially similar to how I passionately hate the old "It's Pilum of Fire but with range Sight." It's a different thing, give it a different name.
  2. @silveroak and @Heru_Kane have already brought this up. I'm only mentioning it for completeness: Entities inside the Boundary when the Aegis is cast brings a lot of plots and even have support in games mechanics, in the Covenant Hooks. @Christian_Andersen points out that it need not be a huge problem, but it's still worth thinking about before closing the door on these plots. On the other hand, I actually fairly strongly favour giving the troupe/PCs/players a "safe place"/home which is hard to attack, since it moves us away from the murder hobos made famous by That Other Game, and makes players more comfortable investing in the covenant.
  3. Case 1 for enchanted items. Being present here means being within the Boundary during the casting of the Aegis I assume? They by definition cannot be inside the Aegis before it's been cast, obviously :wink:
  4. All items created by an Aegis native are considered native? For all time? Interesting.
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From what I can see, this works as the current version, while clarifying a few of the otherwise questionable parts (e.g. direction of penetration if a being enters with effects on itself, how items are resisted, suppression of sustained magic rather than disenchanting). So overall it looks good to me.

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In my Saga we use "Active", "Passive", and "Other". While we use a different structure then the one David suggested (Passive were at the ritual casting but did not take part in it -or- have an invite), "Invites" from Active people place the invited into the Passive category.

I agree that adding an "Active" ["Casting", "Participant", etc] category to the "Native" and "Foreign" categories for those who took part in the casting and can issue an invite is easier.

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Very smooth version. Reposting what OneShot pointed out earlier - I think Parma Magica being dispelled is a change from previous versions.

[quote="OneShot, post:172, topic:170018"]
I was quite sure, that the Aegis did not affect a Parma Magica. Also because of:

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Globally, I like the presentation (it might be a little wordy, but it is mostly very clear, and that is the crucial part). I also think it mostly maintains AotH "as written" in ArM5.
I'll highlight a few points that I think may be somewhat unclear/problematic; these are also the only ones in which this version of AotH differs from the AotH "RAI" you had posted before.

I am not sure about the meaning of "and harmlessly".
My best guess is that it's just a pleonasm, or that it wants to reassure the reader that it does not count as a "failure" in those cases in which trying, but failing to, invoke a supernatural effect produces negative consequences for the invoker (hermetic fatigue, divine tragedies of hubris, maleficia failures etc.). However, as written it might also generate confusion: a witch's broom flying that fails in flight ... probably does not fail "harmlessly". Or maybe it does, and the text means that it fails slowly, with the witch being able to land safely?

While I understand many people like it better this way, I think this is a departure from what was written. Far more importantly, it makes things unclear and very hard to adjudicate outside these three, specific cases.

What does it mean to "automatically sustained by the underlying magic", and to which other effects does this apply to? I think a lot of troupes would wonder whether this would it apply to a folk witch's familiar bond too. Or to an effect such as Immortality of the Forest (GotF: p.38), or the immunity-to-aging power granted by many Criamon paths. Or to the Etin-mod (RM p.83). Or to Virtues granted by e.g. Magic or Faerie creatures via the Grant Virtue powers (RoP:M p.38). Or to the power of Skinchanger skins (ArM5 p.48).

Intuitively, many of these things are "similar" to hermetic familiars, talismans, and longevity rituals, so there's a vague expectation that they should be included too. At the same time, they are somewhat different, so it's not clear.

Unfortunately any clarification might be problematic. Including them, makes the inclusion fuzzy and hard to adjudicate. Excluding them (i.e. saying that only hermetic familiars, talismans, and longevity rituals are "sustained" and resurge) not only runs against the current wording, but more importantly changes the current balance of power. It's a very tough choice to make.

What does it mean "not to have a Penetration"? Could you bring another example outside the Parma Magica? For example, does a Purifying Touch (ArM5 p.44) "have a Penetration"? In general, it seems to me that this sentence creates more trouble than it solves. AotH internally reduces casting totals and penetration. If these are not applicable/relevant, there's no need to say that AotH produces no hindrance.

It's slightly unclear what "this" represents here. Does it mean that none of those powers are hindered by the AotH, or none of those without casting totals or "a penetration"?

How about animals? Non-sentient things?

I think that the sentence "or is replaced with a new one in which they did not participate." creates more doubts that it clears up. It seems to suggest that a way to dispel an Aegis is to cast another Aegis on the same boundary. Is this intended? It should not be the case, from everything else written about the AotH and hermetic magic in general. It also creates questions about what happens when the old Aegis and the new Aegis are over different, but overlapping Boundaries.

What about sentient ones? Also, note that "unlike Creatures with Might" it's technically correct, but confusing because the class of creatures that can be native to an Aegis is wider. I think "creatures" would be clearer.

Someone native at the time the item is created, or native at the time the item's "nativity" comes into play?

Note that this means that a ... Gorgon shield, that turns to stone anyone striking it, if carried by someone foreign to the Aegis and struck by a native of the Aegis, petrifies said native. Is this intended?

Also, this seems to contradict the statement above, that only magi are customarily natives to the Aegis. Though I guess it could be read as saying that only magi are "uninvited natives", and covenfolk are invited on a need-to-operate basis?

Finally, note that this is a change from the AotH as written. If that is acceptable, treating items as creatures - saying that they can be explicitly included in the casting, or they can be invited in later, solves all these issues, as well as those stemming from a demonic item that suddenly has so much more power than a demon to bypass an Aegis.

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