You shouldn't be able to change the Aegis from Boundary to Structure, by RAW. Actually my approach doesn't. Since boats also fit the definition of a well-defined man-made boundary, the boundary target applies. What you don't get to do is save on a level of magnitude by changing it to "structure". The next step is ignoring the sidebox that says boundaries can't move. That is really where the house rule is.
1 Like
I think this post of OneShot is a good starting point to look at Boundary in the broader context of spells targeting a "place" (T:Circle, T:Room, T:Structure and T:Boundary) with a Duration longer than Momentary. The crux of the problem is: what happens if, after the casting, the place and/or its contents move?
There are basically three different ways in which ArM5 treats these spells, one unique to the Thomae's chapter in Legends of Hermes (and T:Boundary), and two common across books and Targets. I'll illustrate all three with OneShot's example of a T:Room D:Sun Curse of Circe, that turns people in a Room (let's say, a tent) into hogs.
-
the magic remains fixed in space. This is how LoH answers the question: if you cast an Aegis on the island of Delos, when the island moves a Delos-shaped patch of Aegis is left in the middle of the Aegean Sea (and Delos is no longer protected).
To go with OneShot's example: a D:Sun T:Room Curse of Circe, that is cast on a tent, remains fixed in space when the tent is moved or dismantled. Until the next sunrise/sunset anyone entering the area where the tent was, gets transformed into a hog, but reverts to a human as soon as he leaves that area. If the tent is on a cart moving in circles, people staying in the tent periodically turn into hogs (when the cart reenters the original casting area) and then back to humans (when the carts leaves the area). -
the magic is attached to the place. This becomes different from 1. only if the place can move, or can cease to exist; so for a lot of spells like The Shrouded Glen it could be either way -- it's not clear from the description. It's explicit (for T:Room, Structure, and Bound) in the case of the Living Ghost's Haunt from TMRE. It's also obviously the case for non-momentary spells that affect the contents of ships, such as the T:Room Ward the Drowning Waves from MoH.
To go with OneShot's example, a D:Sun T:Room Curse of Circe cast on a tent, for the spell's duration anyone entering the tent is turned into a hog, and remains a hog until leaving the tent. This remains true even if the tent is moved around on a cart. If the tent is destroyed, the spell ceases. -
the magic is attached to the contents. The place is relevant only at casting time: those in the place at that time, are affected for the entire duration, no matter what they do afterwards. Those not in the place at casting time are never affected, no matter what they do afterwards. One such effect from the corebook is Incantation of Putrid Wine.
To go with OneShot's example, a D:Sun T:Room Curse of Circe cast on a tent, then the unfortunate victims can leave the room but will stay as hogs until the next sunrise/set -- conversely, people who enter the room after casting are unaffected.
Ideally, only one of 1,2,3 would be valid for all "place" targets. This would be simple and clear all arguments.
Unfortunately, I think that 2 and 3 are too widespread over all books (and over all Targets) for one of them to disappear. Also, they are both common in folktales. So we probably have to live with the idea that whoever designs a spell can choose between 2 and 3 (at a minumum), at least for some Targets. Saying that 2 and 3 are infeasible only for T:Bound, as LoH, just creates a mess in my view -- and negates some very valid sagas that people are running, based on ships, moving islands (like Delos), and cloud-top castles.
Should we allow the spell designer to also choose 1? Keep in mind that the only reason 1 was introduced was to explicitly forbid 2 & 3, not to allow some interesting and "appropriately mythic" application of 1. And frankly, I cannot imagine any such application. So, since if you allow Boundaries of type 2 & 3 to exist you remove all existing reasons LoH's insert, I'd just disallow 1 across the entire Target spectrum (changing the LoH insert into something like "The mystery of the missing Aegis").
2 Likes
You are aware that I could just say: yes, good that we agree!
Yep. Just as you inadvertently said above. Of course, casting that Aegis takes at least an hour, during which its Boundary must not move or waver, and it also takes at least 4 pawns of Vis. If there is the chance of change in the Boundary during casting, the SG is entitled to request a stress roll even if the caster has mastered the Aegis. If there is a change, the casting fails and might botch.
So casting lots of Aegides "just because" is a troublesome and expensive fool's errand. All the benefits of success would also depend on Aegides stretching out to the lunar sphere - an unlikely house rule.
You need to have a rule, what happens to an Aegis - or any T: Boundary effect - cast, once that Boundary gets tampered with. The generic rule is, that a Target parameter no longer matters, after casting is done. All that remains are the beings or objects affected by the spell for its Duration. There are no exceptions - like those for T: Circle - described under ArM5 p.111f Spell Design for T: Boundary, T: Structure or T: Room. LoH p.123 box A Note on Boundary Effects just spells this out clearly.
EDIT: As is spelled out in ArM5 p.114 Magical Wards, their "target is the thing protected", and in case of T: Circle wards the inside and outside of the Circle from effects from the other side. The T: Boundary Aegis is a modified extension of Magical Wards, also protecting the area inside the Boundary.
I'm up for 2, in that something like an Aegis will stay with the moving structure or castle or something. I find that this opens up more things then it closes and to me that is where the benefit is.
I mean if you had a saga where the player magi have a covenant on a boat then saying 'your boat has an aegis' just works with the game and the intentions of the players and thus is maximal fun for everyone. WHY make it more annoying than it needs to be by saying "sorry, nope, no aegis for you!"
One could also solve the Thomae Castle problem by saying 'It did have an aegis, but the griffons that destroyed it just so happened to hatch there and so were considered as part of the wards when the next casting occurred."
1 Like
Just so I'm clear and there are no hard feelings where no slight was intended - I was doing a satire of the rule which you quoted, not you. 
The spell's Target parameter is one aspect of its targets. Its Form is another, that is equally important. Rarely T: Room, T: Structure and T: Boundary spells target all of a place - most of the time they target specific types of beings, things and general stuff in a place. Wards and the Aegis are rather an exception here, treated by the Magical Wards chapter and the Aegis description of ArM5.
You can't without a house rule or at least a Major Breakthrough (see ArM5 p.161 last paragraph). But if an Aegis for your ship is of utmost important for your saga, such a Breakthrough could in your saga well have already been accomplished by a follower of Notatus.
Such a breakthough better be kept secret in a small cabal! Movable Aegides in general can also revolutionize magical warfare by siege towers, assault ships, flying fortresses (with magical bombs!) and magical digging machines protected by such Aegides!
You bring a fair point which I'll take some time to consider.
You misunderstand me completely - which happens. But I believe to have explained myself here already sufficiently.
Hi,
I suppose I'll give it a go.
Let's start off with what these targets are. A target of individual or group is of the form of the spell. To Target a group of minds I use mendham. A group of sheep? Animal. But targets such as room, structure or boundary r containers. These are arbitrary constructs that have nothing to do with the form being affected.
The other thing that I think I remember correctly is that a spell takes effect immediately and lasts for its duration rather than continually applying itself over its duration. So if I mind control everyone in a room for a month, the people being mind controlled stay mind controlled even when they leave the room to execute my nefarious demands, and people who newly enter the room are not themselves mind controlled. New paragraph
In a similar way, if I have a ship, and cast a spell that affects everything on the ship, everything is affected even when it leaves the ship, but anything that boards the ship is not affected by that spell. Also, the ship moving or being destroyed has no effect on this. The spell used the ship as a container to satisfy the target specified, but the magic itself affects the forms at spell casting time. New paragraph
It is possible to create weird spells that behave differently, such as treading the Ashen path, but these are exceptions that must be specifically designed to act in this way and require permission to work because it is not always apt. And, of course, the spell gets an extra magnitude or two for being special.
But let us go back to normal spells.
If I have a spell on a ship that kills the rats, I need to reapply it to kill any new rats. If I have a spell on a ship that controls magic, I need to keep applying it to control magic, unless we have some idea or concept of their being a magical heck I'll call it a field that is being controlled, in which case that field is controlled for the duration. This is a modern sounding term, but it seems closest to what an aegis is doing. Otherwise, totally leaving aside movement, how can it affect any new magic introduced to the area? After all, there is no form for area, certainly not them. Or, we can say that in aegis is similar to treading the Ashen path, and that is what makes it special. And then we do not need the field or some concept like it because the spell continually and repeatedly affects its form as usual. New paragraph
I think that this ambiguity will help us solve the problem. If the spell had an immediate effect that changes the local magical field, moving the boundary will do nothing, nor will eradicating it. The spell has already had its effect, which will last for a year, similar to the way a mind control spell that affect the boundary does its thing one time and then persists upon the affected Target. New paragraph
But if the spell is like treading the Ash and path, and is therefore weird, then moving the boundary will will affect the new region. And this would then leave us with a question of what happens to the previous region. If it is exactly like treading the Ashen path, which applies a momentary effect repeatedly over the duration of the spell, the previous region affected by the aegis is no longer affected. But if the aegis not only applies itself repeatedly for the spell duration, but each application persists for the spell duration, then you get this ever growing aegis as the region affected by the spell changes. Either way, destroying the boundary would stop any future applications of the aegis, because the boundary defined by the spell is gone. This means that the momentary version applied repeatedly for a year would stop as soon as the boundary is no longer a valid boundary.
So, I think there are three valid interpretations for what happens to in aegis. The most simple and straightforward is that when the boundary moves nothing changes and the region previously affected remains affected and no new region is affected. Destroying the boundary similarly has no effect. But the rules support other interpretations that would apply specifically to spells that are designed that way. The aegis is a very special spell and perhaps is designed that way. New paragraph
What about haunt of the living ghost? My answer is it's a mystery virtue, it looks like a spell but it's weird and different and not completely hermetic anyway. So it can do what it wants. But we can say, if we want, that it works like treading the Ash and path, continually maintaining the ghost as though it will recast every moment. New paragraph
This might be wrong in all sorts of ways, because I don't remember my books and I certainly am not about to open one because that would hurt. But that's what it looks like to me.
And now I get to collect some experience points in magic theory 
Anyway,
Ken
As I mentioned once elsewhere n this topic- if your boundary target can move, what happens when your flying castle with an aegis flies over a magical tree with might:10? Does the castles aegis cause the castle to bounce off? Does it uproot the tree? This is not a simple or trivial change we are talking about.
No. That's one "type" of "place Target" (I call it type 3, above). Like Incantation of the Putrid Wine, that makes all liquids in the room at the time of casting vile, and they stay vile even if brought out of the room, while no new liquid brought into the room later becomes affected.
But another "type" exists (I call it type 2, above). It affects all things that happen to be in the place during the entire effect's duration, while they stay in the place. The Shrouded Glen: anyone in the target forest gets lost, for the duration of the spell (yes, this is mind control, constantly renewed on new folks). Well Without Light: all light within the target structure is smothered for the duration, including new light you bring into it. Aegis of the Hearth: opposes foreign supernatural powers brought into the target Boundary for the duration - those that can get out are no longer opposed.
I'd say this is more common in folklore and myths, and also less prone to the type of abuse where you create a temporary "place" (e.g. a room) via magic for the briefest duration, so that you can then target everyone within it with a long-lasting effect ... and then you just "erase" the room but what you have ensorcelled stays ensorcelled.
Assuming that the aegis extends all the way down to the tree, the aegis enfolds the tree - that suffers an appropriate reduction of its magical puissance until the aegis moves away.
Note that a mobile aegis enfolding an immobile tree is different from a mobile tree (attempting) moving into an immobile aegis! Remember that many of the "symmetries" of newtonian physics do not apply to ArM5 cosmology: if a magus turns into a giant through a low penetration spell, and then tries to punch a real giant of sufficient Might, his punch is stopped by the giant's MR... but if the giant then punches back the magus, the fist connects with full force!
And that simple rule is confirmed by LoH p.123 box.
Quite. TMRE p.73 The Haunt uses the Target parameter of p.71 Bind the Living Ghosts to define the Haunt. This goes beyond the standard Target parameters from ArM5 p.111ff Spell Design.
I think this has been resolved in the process of sorting out Ring/Circle, if taken with the sidebar in LoH.
Is there anything major outstanding?
It's still not 100% clear to me how it's been resolved It seems to me that what you are saying is the following:
A magus can define at the time a T:Boundary spell is invented how that spell works. In particular if:
a) the spell affects for its duration everything that was, at the time of casting, in the boundary, or that
b) the spell affects for its duration everything that is in the physical space that was occupied by the boundary at the time of casting.
The magus can however never choose that:
c) the spell affects for its duration everything that is in the boundary.
If that's really the case, one would have to at the very least
- explicitly state in the corebook, rather than (only) in a sidebar of a "highly non-core book".
- explain that in this, boundary acts differently from all other Container Targets, that work instead as either a) or c), and never b).
This is really important, because it's very easy to assume that if a T:Circle spell moves with the ... Circle, a T:Room spell cast on a boat moves with the boat, a T:Structure spell cast on a ship moves with a ship, then a T:Boundary spell cast on a ... ship! moves with the ship, rather than leaving behind a ghostly ship-shaped afterimage of magical energies as it does in b). - errata Haunt of the Living Ghost
- make sure that there is no published covenant (or suggestion of a covenant) with an aegis on a "Delos-like" moving island or on ship/ fleet of ships. This last is rather sad, I think, because it rules out many interesting saga possibilities based on the concept of Semita Errabunda, but with a covenant that moves "classically" rather than by warping space.
As mentioned above, I think this is really a sad choice (in that reduces fun game concepts, complicates the game, and introduces a mechanic (b) that definitelly is not "mythic"); and it would be much more effective to simply replace the LoH sidebar with one on "The mystery of the missing Aegis" offering tantalizing hints about why Tomae had none ... and ultimately leaving it as a mystery for players to solve.
But in all fairness e.g. One Shot sees it differently.
Or T:Boundary can only be cast on unmovable entities. By stating it explicitely in the target definition, readers will realize this constrain does not apply to T:Room.
Very few things are truly unmovable.
I don't think it's an issue for most AotH.
Are you thinking of the boundary of a forest when you cut up some trees?
Or are you thinking a forest* can move?
*using forest as a default entity, don't expect too much sense.
Well, imagine a covenant on a mountain peak. What if you use a rego terram.spell with enough size magnitude to move the mountain a few miles away?
2 Likes
From tL&tL, p.20:
one Merinita magus even moved a hill two miles south!
[to make access to a vis source easier]