Questions about Boundaries and Ships

Hi, I've got a question that I have not been able to find an answer to, and was hoping someone here knew the answer or could point me in the correct direction. I know there are spells to affect things like carriages or ships that use room or structure, and which stay with the vehicle as it moves.

What about the boundary target? As written, "The spell affects everything within a well-defined natural or man-made boundary," so if I wanted to cast Aegis of the Hearth on a ship, that reads as an OK boundary to me (well-defined are the outer edges, and it is definitely man-made). But if the ship moves, would the Aegis move with it, or would it be "floating" in empty space? All of the examples in the core rulebook are static and unmoving (walls of a city, edge of a village), or else I would say it would work.

The spell is defined by its boundary, and if the ship moves, you definitely would not have a spell effect left behind in "empty ocean."

If your Aegis ritual walks the outer edge of the ship, and your SG rules that an effective boundary, then you'll probably also rule that the Aegis is going to move with the ship. You could, however, rule that the effect is stationary, the ship moves, the boundary is no longer there, and so the spell simply fails. As if, for example, a covenant casts Aegis around a fence, and the fence is destroyed. No boundary, no Aegis.

Note that the covenants who use ships -- Northern Seas is the mist detailed example -- don't use the Aegis. A ship is a clear Structure, but as you note, using a ship as a Boundary is not really supported by the canon. I agree that a ships deck seems like an easy boundary, so all of this suggests that, actually, the less happy option might be the official answer: the boundary would work only so long as the ship is parked, and when the boundary moves, the spell fizzles.

But if you want to let the players do otherwise, none of them are going to complain!

The issue is ruled explicitly here:


I'm genuinely surprised that the Boundary effect remains active after the physical boundary itself is gone. I'd probably rule otherwise.

But there's your official answer.

The ArM5 p.112 provisions for ending a Target Circle spell when the Circle is broken are missing in the p.113 description of Target Boundary.


I believe that the "immobile Aegis" is actually a change from previous editions.
If I remember correctly, Land of Fire and Ice (the Iceland supplement for 4th edition) had two ships that travel to Iceland, each protected by its own Aegis from Iceland's guardian spirits.

Thanks for you feedback, everyone!


I'd recommend ignoring this official rule. It makes no sense.



The rule is a consequence of Boundary being a Target parameter of a spell. Unless specific provisions are made for specific Target parameters (e. g. T: Circle), these do not interfer with the Duration of the spell, or its effect after casting.

  • If I use a T: Individual Muto Corpus spell to magically increase the size of a human to +2, that spell has its normal Duration. Even though the new size +2 of that human would have prevented her from being targeted by the spell in the first place.

  • If I use a T: Group Muto Corpus spell to magically turn the hair of 10 human targets blond, the Duration of that spell is not affected, if the 10 new blondes then disperse into a crowd and thus no longer are a well-defined group.

  • If I use a chalk line - certainly "a well-defined natural or man-made boundary" - to delimit a T: Boundary for my Aegis of the Hearth, and after casting the ritual immediately erase that line to keep the covenant's enemies guessing at the extent of my Aegis, this does not eliminate the Aegis before the end of its Duration. Neither would redrawing the chalk line move the Aegis.

  • So, if I use a ship's guard rail to delimit a T: Boundary for an Aegis, and after casting the ritual move the ship or burn it, it is logical to have the Aegis stay where it was cast: the state and place of the Boundary delimitation after the casting does not affect the Aegis.


Could you not go around the problem by using Structure instead of Boundary ?
For a ship, Structure is perfectly suitable as it includes both the vessel and its content. You might have to add a level for increased size depending on your ship.
To my knowledge, Structure can be mobile, thus avoid the issue of the moving boundaries.

Now, is it easy to reinvent Aegis with a different target parameter, that's a different story - The aegis being known as not fully integrated into the Hermetic Theory and acknowledge as being of the few canonical Major Breakthrough.

There has been lenghty discussion about having Aegis with a shorter duration than year, and it was acknowledge as potential for all kind of abuse. Yet, as usual with this kind of touchy discussion, if it allows you to tell an interesting story, the Golden rule is " Discuss with your troup, have fun and go ahead".

My take is: changing the target parameter does not change the ritual aspect of the spell, so it leads to less complicated consequence than having Aegis becoming a non-ritual spell by changing both its duration and target. However, is Aegis can be downgraded to Structure, what does it prevent to be reduce to Personal, thus giving a Parma-like effect achievable through spell ?
So think about the consequence of allowing such change, or limit it scope to suit your story without creating too much ripples.


Sure, because it is still Ind. (Though the spell already does account for size.)

Sure, because the target is 10x mass, in more than one Ind. The issue at casting is the ability to designate them, not what the target is.

a) No. The boundary defines the target. If there is no boundary, there's nothing for the spell to apply to anymore. Note the conversation regarding Haunt of the Living Ghost: Boundary is a lot more resilient than other targets, but completely obliterating it destroys the spell.
b) Sure, because the new chalk line is a new Boundary, and no spell has been cast on it yet.

No, because if I destroy the Target it is gone. Unlike the Ind, unlike the 10x mass of Ind, neither of which is gone. For Room, Boundary and Structure, the target is the room, boundary and structure, respectively.

But if I move the ship, the Target has not been destroyed. It has simply moved, the same way if I cast a spell targeting an Ind, the spell moves with the Ind.



Personally, I'd be fine with writing that one off to "Boundary is a ritual effect with an implied relationship to the earth that is not fully integrated into hermetic theory."

The official ruling on the flying castle, to me, makes no real logical sense in the rules of Hermetic magic. I'm actually happy with the T: Boundary spell fizzling out, or moving with it. Having it left behind as an echo seems incorrect.
My interpretation of D: Ring, T: Circle would be allowing movement as well. It I had a Circle inscribed on a stone slab, and put in a cart, of I warded the circle and drive the cart to the next town, wouldn't the Ring move?

If I recall correctly, Covenants has an example of hermetic Circles/Rings inscribed on the pages of books.
That would strongly imply that Circles/Rings tolerate movement, and a certain level of "bending" too.

Hence, if I cast ArM5 p.131 T: Individual Preternatural Growth and Shrinking onto a Size +1 human, making her a Size +2 human, that spell does not immediately fizzle out because it would not affect a Size +2 human by


I don't know what you mean by "the conversation regarding Haunt of the Living Ghost". This?

This just spells out, that destroying the boundary markers does not destroy the Haunt - the bounded area - or end Bind the Living Ghost.
But it appears that you mix up T: Circle and T: Boundary here. Let's have a look at the definitions, then:

So, a spell affects its Target within Range at the time of its casting, and afterwards its duration is governed by it's Duration parameter. There is an additional, specific provision for a T: Circle spell ending also if the circle is broken or destroyed. But there is no such provision for a T: Boundary ritual ending in such a case - just like there is e. g. also no provision for a T: Individual spell ending, if after it was cast its Target outgrows the allowed size. This is, what LoH p.123 box A Note on Boundary Effects builds on.

Here you misunderstand the ritual's Target. By the above ArM5 p.113 quote, this Target is not the boundary, but "everything within" it. And that is clearly not gone by obliterating the boundary markers.

Right this time - though you still misunderstand the target.

To target the ship that way, you would have used a Herbam T: Structure spell with requisites (see Ezechiel357's

Moving the boundary of a T: Boundary ritual, and still having it target "everything within" at any time after moving, is a misapplication. LoH p.123 box A Note on Boundary Effects spells this out clearly.



Exactly this. The extreme destruction isn't about destroying the area, but about destroying the bounded area. That is, the boundary must be obliterated. It isn't possible to destroy an area! One can destroy any of a bunch of Forms within an area, but not the area itself. There is no Hermetic Form for that. The sentence before talks about the boundary changing, and that change doesn't make a place cease to exist. But the boundary is the thing that actually defined the area as a place, so sufficiently extreme destruction of that boundary makes the the bounded area cease to exist as a place.

Again, the thing being destroyed is the boundary.

I was kind of waiting for this. And it seems reasonable. Except that many Boundary spells don't simply affect the things within at the time of casting, but continually affect anything entering the Boundary for the duration of the spell. This includes the Aegis, which works against magic that wasn't present at the time of casting. So... no.

No mix up.

Same response. No misunderstanding.

Indeed, hence my recommendation to ignore it.

In practice, many canonical Boundary spells do not simply affect things in it at the time of casting. If that were the case, I'd agree.



It appears, that I need to get some terminology distinctions in place before we continue.

(1) Boundary capitalized and T: Boundary denote the correspondent Target defined on ArM5 p.113.
(2) When I cast a T: Boundary ritual, I use boundary markers to delineate a "a well-defined natural or man-made boundary" (ArM5 p.113). Walls, guard rails, rope rings laid out, chalk lines, lynchets, forest edges, shore lines, ridges and others may be such boundary markers.
(3) The area of effect of a T: Boundary ritual has borders with the world around it.

The casual use of "boundary" for all the three different things - also in the ArM5 books - has made our discussion very difficult and susceptible to mulligans.

Some active T: Boundary spells - like the Aegis - affect beings and things either trying to enter its area of effect, or entered after casting. So, while a T: Boundary effect persists, its borders are indeed very important.


The bounded area is still the area: it doesn't "cease to exist" from damage to its bounds. The text above considers the conditions to destroy the Haunt. It does not propose or consider the destruction of boundary markers as a viable way of doing so: only T: Circle Haunts are vulnerable to something like this. The TMRE p.71 low wall, that grogs build at the request of Graculus Hopeful-To-Become-a-Ghost to define the future border of his Haunt, is not meant as a trap for stupid players to be cheated out of their hopes.


What defined the T: Boundary area at casting time were the boundary markers. No ArM5 rules text requires these to be still around after casting the spell. The idea, that such boundary markers are necessary to mystically keep the borders of the T: Boundary area in place, is yours. It is contradicted by LoH p.123 box A Note on Boundary Effects.


This explanation makes sense to me. A Boundary marks out and defines an area as being somehow special, "sacred space" if you will, like the boundary of a cemetery. As long as the defined special space remains recognizable Boundary spells can remain in effect. A forest may expand or contract as trees grow or are cut down along the edges but is still recognizably the same forest unless "extreme destruction" occurs. A purely artificial boundary, such as a chalk marking around a covenant, is resilient enough to survive considerable damage to that marking but not total erasure of it. This is much more stable than a Circle marking, which is destroyed by the smallest scuff.

TMRE p.71 Bind the Living Ghost is a unique, personalized Mystery ritual anyway - so using your imagination when fleshing it out does not condition your Hermetic magic, but helps your saga.



Exactly this.
I hope you're not pruning quotes to make it seem that I agree with you. In my original, it is clear that 'this' does not refer to "destroying the boundary markers does not destroy the Haunt - the bounded area - or end Bind the Living Ghost." I refer specifically to the text.

More to the point: If the boundary is defined by the boundary markers, then destroying the boundary markers destroys the Boundary spell.

My entry into this conversation advised ignoring said box. Consequently, I have nothing to say about it beyond considering it a single botch.