A Guide to Aegis of the Hearth

I'm not going to argue that one with you because I'm of the school that says it's a spell and must penetrate like any other one, and I agree with you that it makes things more interesting. In two different sagas we've chosen to cast it forcelessly. Once was a political move to allow faeries to pass through (They'd already been using part of it as their magical road.) so they wouldn't get pissed off. In that same saga there were magical butterflies that had to enter as part of a process for one of our vis sources, and we didn't want to lose it. So we had two reasons to allow supernatural beings (with Might 0 in one case) to enter. But we wanted some protection so we were going with as high a level spell as we could cast, especially since we didn't want to penetrate. The other saga, which didn't really get very far, had a similar vis issue. It's fun having to make such decisions. Do you go with added safety at the expense of something else?

As for the air comment, you can strip air from an area around a magus with Parma Magica without needing to penetrate, like making a hole underneath. The air inside their Parma Magica won't be destroyed, but it won't last long and won't remain in place, either. Of course, this won't kill the magus instantly, so running or teleporting or the like could get him out of it.


I could prove it if I had the Gödel number to Aegis of the Hearth, but I don't think it exists. :wink:

{erm, yeah - it's undecidable.}

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Andrew, one word: it's the only major breakthrough known in the book apart for the parma magica (hermetic breakthrough). Breakthroughs do not necesseraly follow normal rules because their purpose is exactly to enhance and improve them.

I agree that the Aegis of the Hearth is a breakthrough, and can follow different rules. However, I think Andrew's point is this: When a spell breaks the rules, it explicitly states how it breaks the rules. The description of Aegis of the Hearth does this in several places. However, it makes no statement about requiring penetration, so the simplest solution is that it does not use special rules. It is still a spell, unlike the other known Hermetic Breakthrough (Parma), and follows the rules for spells. The spell description of Pilum of Fire does not state that it requires to Penetrate, but no-one argues that it does. Treading the Ashen Path doesn't follow the usual rules in one certain respect that is clearly indicated in the spell description. However, I haven't ever seen anyone trying to argue that because Treading the Ashen Path deviates from the rules in this respect, it also should/could deviate from the rules in other respects.

However, when it comes to wards and the Aegis, people have sometimes assumed that the rules are different when there is no evidence to suggest that they are. In the beginning of 5th Ed I was as much a victim as everyone else, thanks to the burden of previous editions. At least for wards we have definite confirmation that they do need to penetrate -- i.e. they are not exceptions to the rules. Let us not posit plurality without necessity*: the Aegis needs to Penetrate to affect creatures with Magic Resistance within or attempting to come within its bounds. The breakthroughs in this respect cover invitation and casting tokens, as well as the damping effect without a Perdo requisite.

I shouldn't need to say this, but I will: you can play it however you want to play it; it's your own game. But I would consider an Aegis without Penetration as a house rule, not RAW, regardless of how many people play it this way. In our saga, we have a 25th level Aegis cast every year using a Wizard's Communion of 4-5 magi, and nearly every year it is cast with Penetration in excess of its level. Without an extreme specialist that's probably the only way it will get cast, but then that's why we have Wizard's Communion...


*apologies for this mangling of Occam's Razor

Here's a really fun one I just (re)found...

Page 76, col iii - "A Covenant". (This is the section that describes different reactions to The Gift.)

In the preface to those specific descriptions, it says
"These descriptions... also assume that the guard room is outside the Aegis of the Hearth."
Huh?! :open_mouth:

Is that "implying" that the Aegis would have an effect on the reactions, on The Gift, perhaps the way that Parma does?! :open_mouth:

No. (That was a rhetorical question.) But what I think it does imply is that, for a (brief?) time during editing, Aegis for 5th ed might have been conceived that way (intentionally or mistakenly), but that was overruled - just not every reference to that short-lived interpretation was purged.

Rules are a paradox, any rules, because they are written language. Over-reading them, reading the language too closely, can almost always give rise to contradictions and holes, but they are all we have. So they must be taken with a grain of salt, with "common sense", if we are to make any sense of them at all. And if, as the esteemed Mr. S points out above, different Troupe apply different "common sense" toward that goal, that's fine, even expected, even encouraged and perhaps at times invited by the rules themselves.

If your troupe needs specific distinctions at this level, figure out the rules that work best for you, and enjoy.

I would have assumed there would be some sort of guard room outside of the Aegis just to welcome magi without pissing them off. For one thing, it would be nice to be able to introduce yourself without losing your active defensive spells and having casting penalties. Otherwise it could be like jumping out in front of the guns to wave a white flag, getting shot, then pulling out your flag. Additionally, it would be nice not to be forcibly separated from your familiar in order to introduce yourself. You are true friends, after all.



All that is well and good, C - how does it qualify/change reactions to to The Gift? That is what that section is about, not how to be considerate to Hermetic visitors..

Oh, I see what you're saying. Hmmm... When, perhaps if a magus it outside of an Aegis the reaction penalty of his Gift is blocked by the Aegis just like it is by Parma Magica since it has no penetration? So by putting a mundane guard outside of the Aegis it's easier for the guard to identify magi who come to visit as genuinely being magi?


This would work if the negative effects of the Gift were something specific and immediately identifiable (to those in the know). But I don't see it this way: I think that the negative effects of the Gift manifest extremely subconsciously in people (not protected by Parma Magica). Only over time could a person notice enough negative treatment to start to think it might be the Gift causing it (and it might not be either); noticing this from one's own reactions would take a fantastic self-awareness as well. (I definitely don't think a magus can just walk around a city with Parma down until he spots a child and says Hm, that child makes me feel uncomfortable, she must be gifted, let's go home in time for lunch.)

I agree. I was looking for a reason, not understanding what it is. That's why I wrote questions.


The Aegis doesn't block the affect of the Gift, only Parma does.

The section quoted on ArM5 page 76 isn't implying that the visitors being outside or inside the Aegis changes the affect of the Gift. It is just that what the guards would do changes if the visitors are outside or inside the Aegis when first encountered by the guards. Like in RL, if a visitor approaches the gate-guards at a military base, the visitor will be dealt with rather differently, than if he is unexpectedly encoutered by guards at a post somewhere inside the military-base.

A visitor who is first encountered by guards inside the Aegis is probably some kind of emergency. Perhaps, a scrying attempt, another sort of supernatural imposter, or at the very least he is a legitimate visitor trying to go somewhere he isn't meant to be going (like a guarded laboratory). So the guards are likely to be much more hostile.

No, but if you are a guard at a covenant and a weirdo approaches and wants a token to enter, it is a good bet that he is a magus. Or at least some other sort of supernatural hazard.

The 2e rules explicitly state faeries and daemons are affected.

The 3e rules resemble the 2e rules.

The 4e rules say beings with Might (no qualifier) are affected. It explicitly follows this up by stating that magical, Infernal, and faerie beings are affected.

I haven't run into something in 5e that extends Aegis of the Hearth to cover Faerie and Infernal Might, but I would play it that way. (It would seem largely useless without the additional coverage.)


I've just read 5e Aegis of the Hearth again, is also says Might only (no qualifier). The explicit portion in the 4e version stating magical, infernal, and faerie being are affected has been omitted, but again, it says Might, not Magic Might. Any Might would be affected.

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Apart from the spell description?

Read the middle column, ArM5, page 161.

Aaack. I edited the wrong section. I meant to edit the penetration section. Doh!

OK, fixed now.


Is it unholy threadmancy if it's only been a month since the thread died down?

So, what about the boundary problem? I notice that this has come up in the Base Camp game.

The text of Aegis, on page 161 of the MRB reads, at the very end: "...any magus trained in the Order is capable of inventing versions of the Aegis with the above parameters, but at different levels. Inventing a version with different parameters, however, would require a similar breakthrough and years of research." The parameters are R:Touch, D:Year, T:Boundary, Ritual

Is increasing the Boundary from the base size to the next size by increasing the level of the spell by 1 magnitude really a change in the boundary parameter? The paremeter is still boundary, it just covers a greater area. It doesn't change it to Individual, Group, or whatever. Also, in previous editions, I don't hink Boundary had a limit in size, it just required an actual physical boundary of some sort.
I'm interested to hear some good debate on this.

I certainly think it's fine to invent a version with extra magnitudes for Size modifiers to the base Boundary size (in fact they did just that in my current saga).

Either that can be done easily enough, or Aegis ignores the size limitation of Boundary - pick the one that gives you the lesser headache - I'd go for the first one.

In 4th ed, Boundary was unlimited in size, except that a fairly well defined boundary was needed, as you mention.
Unfortunatly this meant you could eg. fireball England (well, England, Scotland, Wales and Cornwell) in a single go.
This has been debated, but it could be argued that you merely needed to be able to seen the coast line, and use the coast line as you boundary. Boom.
It get even worse when you target eg the French coast...
In theory, you could still do this, but would require a number of magnitudes worth of size modifiers, which combined wth the slightly slower Art progress seen in 5th ed makes this less likely to happen. Unless you're playing in Direwolf's troupe I suppose?

Earlier editions yet did not have a "Target" attribute and levels were decided be troupes, not calculated mechanically from a base guideline plus modifiers.

Edit - totally forgot the Targets & Sizes insert info (last paragraph) re default Boundary size. All wrong, smokin' crack, nm.

As I understand it, T:Boundary has neither numbers nor volume nor size nor area to increase. A boundary is a boundary - you don't get "10 boundaries" for +1 magnitude.

And if anyone believes it's unlimited in 5th, they need to grab the reins of their Saga. (Or, yes, go play in DW's game.)

ArM5, p. 113, box, last few lines of Wall o' Text defines a base boundary to be 1 hundred paces (300 feet) in diameter*.
The same size is given in the bold lines below, in the same box.

[size=85]* Thus also neatly defining the length of a pace as 1 yard** :confused:
** So that's where I had that from! :[/size]