Target: Room and unsensed targets

If you cast a spell with Target:Room, does it affect beings/objects/etc within that room that you cannot sense? For example, if you cast a room version of Demon's Eternal Oblivion, does it affect an invisible demon within that room? Is the answer different if you're aware of the location of said demon (e.g. because someone with Second Sight points it out)?

This came up in my last session, where the players wanted to destroy a disease demon possessing a young woman. The Perdo specialist got access to the victim's sick room, and another magus's familiar used Second Sight to confirm that (part of) the demon was possessing her. The Perdo magus managed to spont a Room version of DEO with enough penetration. I ruled that this technique would work, but I'm not sure if it's the correct answer because it seems to contradict the limit of arcane connections.

Another example is casting a Room version of Call to Slumber on a room containing one visible man (that the casting magus can sense) and one invisible man (that the casting magus cannot sense).

The target is the Room.
If you can sense the Room, you can affect its contents, even if you can't sense the contents directly.
Anything in the room, is part of it, so is affected by magic targeting the whole room.
In the same way that if you turn a man into a pig, you turn into pig-parts even those man-parts you cannot sense.

So no dissenting views?

i speak as the player that caame up with the wheeze, so I want to make sure that we have covered all options and not tried to pull a fast one in any way.


First, I do agree with Fafnir that your target is the room, and what that is encompassed within. Second, you are aware that there's a disease demon in there. Wandering down the street and throwing DEO at every peasant you see just because you can do it with no botch dice has no real chance of banishing a demon you can't see. Being told there's a demon RIGHT THERE and then smiting it seems to be stretching the rules just a bit, but the Limit of Arcane Connection states 'cannot affect an unsensed target", its up to you to determine if that's just a convenient word rather than the definition 'target', but I lean towards definition; Just like conjuring a pool of water can get an invisible person wet, even if you didn't know they were there. T:Ring, T:Room, T:Structure all target non-individuals. T:Ind and T:Group are more affected by this rule, so casting a spell to teleport a group of grogs six paces in the air will not hit the two who were behind the corner that you didn't know were there.

My only concern, actually, is if DEO can hit a possessing demon. I'll have to look up the rules once I get my grubby mitts on ROP:I at home.

The idea of hitting something you can't detect inside a room is explicitly allowed, as described on pg. 81 of Hermetic Projects - in the discussion of "how do I get rid of an Intangible Tunnel?" the answer is "first perceive it, then cast Unravelling the form of Vim on it - or cast it on the entire room, if you can't directly perceive it." You don't even need to know for sure that it's there - the text explicitly allows for sufficiently paranoid magi to cast it.

Also, I"m pretty sure that if you have an Arcane Connection to 1 person, and cast a Group spell through a tunnel, it will affect everyone in any gropu that the AC'd target is in. For the same reason that if you see someone's head or hand, you can affect their entire body. Thus, those invisible targets may very well be hit with any relevant spell.

Also, you can hit invisible targets accidentally, or if you have a vague notion of where they MIGHT be, according to the "How to hit invisible targets" section in HoH:S. As such, you can probably hit invisible targets that are inside a group as well.

This tells me that magical attacks are auto-hit, and they have a more-or-less defined area around them that they also auto-hit. So, you can aim for a point of ground, and automatically hit it - and if there are a combination of visible and invisible targets in that area, then you'll hit all of them. Its just that Ars Magica combat is vauge enough that "where is everybody standing" is a bit of an abstract question.

Of course, if a mage can restrict their magical sizing to "the 6 peasents I see", then sure - but I'm not aware if magi can do that freely. (Finesse roll? I'd allow it.) But I think if the invisible peasents around the corner are close enough to be a part of the group, then they're affected - assuming the group doesn't get too large as a result.

They can. It burns off their Might pool first, at which point they loose the possession - and then it starts in on their permanent Might.

EDIT - huh. Actually, it's a bit unclear. RoP:I pg. 33 says "Vim spells may be used on the energumen to target the demon rather than the host; these must overcome the demon's Infernal Might in the usual way, but drain the Possession Might pool, not the Infernal Might."

Which is my understanding. However, Rop:I pg. 121 has a new guideline "Reduces a target's Might Pool"; there's also a spell (pg. 122) that uses this that affects a demon that is possessing someone, but only affects their Might pool.

So, the first seems to suggest that you can just DEO a possessed individual, and it will affect their Might Pool, and then their Might. But the latter suggests you may need to create a separate spell for it.

I would interpret that to mean that you can DEO a demon that is possessing someone just fine (and it burns off their Might pool, and then their might.) However, if the demon is only partially possessing them (they can do that - they invest Might points into the target, but don't physically enter them), then you'd have to use the "burn off might points" spell to clean them out.

Thanks for the replies everyone.

My confusion arose because of the text in Realms of Power: Infernal, which goes on about how you must be able to sense a demon to affect them, and how hermetic magic sucks at this. There was no mention of circumventing this by using room (albeit at +2 magnitudes). Good to know I made the correct call at the time :slight_smile:.

If you use DEO on a possessing demon, it reduces the demon's Possession Might pool rather than the 'real' Might pool. RoP:I says that a possessing demon must spend/invest 1 Might to keep the possession effect active. My interpretation is that when this point of Might is destroyed by DEO, the possession lapses.

The interpretation I used in my game last year was similar to this... If you can sense the demon possessing the Poor Sod, you can target that demon with DEO to berid of the possessing demon. If you cannot sense the demon, you cannot DEO the demon out of the person. (Above interpretations, you can still target room to get around it) However, if you cannot sense the demon, you can't DEO the demon, and casting DEO on a Poor Sod won't banish the demon because you're not targetting it. A completely different PeVi spell could be cast on the Poor Sod to destroy the Infernal Might invested in him via possession, and that would free him from possession.

I'm pretty sure the "you must be able to perceive the demon in order to affect it" is just a restating of the standard Ars Magica rules (Rop:I, pg. 30) - with the implicit assumption being that you can use the invisibility targeting rules with PeVi spells just fine, if the demon is hiding or in its spiritual form, but you know it's in a general area. And if you can target its container or use an AoE effect, they're a lot easier to hit.

Thus, if you can sense the person, then you can target the person as a container for the demon - just as you can target a room as a container for the demon as well. Vim spells explicitly say that you can either affect a specific magical effect on a target, or blindly affect all magical effects on/in the target. (AM, pg. 157) I'm pretty sure that's the justification for "blindly blast the room", and so it can also be a justification for "blindly blast the person".

Serf's parma: Since possesssing demons are not affected by the aegis, they have no might score to be destroyed by DEO.

Banish a possessing demons is hard for hermetic magic: you cannot target a possessing demons because you cannot sense it. Divine powers and other tradition (ex miscellanea tradition: banisher) are good at it.

But possessing demons do have a Might Pool invested in the host, which is what you're targeting with PeVi (assuming one can target the demon!).

RoP:I specifically calls out that possessing demons can get round hermetic wards. If PeVi also couldn't affect possessing demons, I'd expect the same passage to make reference to that fact.

With the "special" guideline found in ROP:TI, sure... if you can sense it. And possessing demons are not invisible creatures, and are not subject to Intellego magic (since they are demons <=> limit of the infernal or whatever is the right name). So you need...

  • not second sight, since second sight cannot see "inside things" (you cannot see through humans, nor can you see through walls)
  • eventually sense holiness and unholiness, but it's not because something is "dark grey" (= fusion between normal grey + black for demons) that this mean "normal human + demon". It could mean a very sinful human, so you shouldn't say "I sensed a demon because you are dark grey haha!"

Without sensing, no targeting for hermetic magic. A vague "guessing it could be there" should not work.

Anyway, it would not work with the DEO guideline.

IMO, without that "strength", demons are cannon fodder for magi (as anything which has might in fact, because penetration and item are so powerful in the hermetic magic). Which the setting doesn't say so, there it is. Demons usually possess human tools (grogs, apprentices or families of magi if they can!)

I disagree on both of those - second sight is all about seeing things you can't normally perceive, and a possessing demon falls under that category. RoP:I is clear that Second Sight can see demons, and I'd expect some text about 'except demon's possessing a host' if it wasn't meant to work that way. Sense Holiness/Unholiness should also work, as it's an ability granted by the Divine Realm, and so isn't confused by demon tricks. If you make the roll, you should be able to see a demon possessing someone, and distinguish that from a very naughty human.

Except if you use T: Room, according to the general consensus in this thread :wink:

I'm not sure about that either. Why can't you cast DEO on targets you suspect of being demons? The spell won't work on them, but I think you can still target them. E.g. you can cast DEO on a faerie pretending to be a demon - the spell won't work, but you can try (and then wonder if it failed due to lack of penetration, or something else).

Are there any explicit rules about this? I do agree that it makes quite a difference to the power of demons. Assuming my reading is correct, there's a strong argument for PeVi'ing your grogs, lab, visiting magi etc. If they're not demons it won't hurt them, and so why not?

If you cast DEO on a faerie pretending to be a demon it will probably pretend that it worked... tricksy faeries.

I don't really understand what you disagree with.

  • Do you think that second sight allow you to see through matters? if that's so, then do your characters with second sight walk on "nothing" since they can see through the earth? if so, fine, but that's entirely your saga, not raw.
  • do you think sense holiness and unholiness tells you what you are seeing? RAW p67 says: "you are able to feel the presence of good and evil". It doesn't say: you are able to feel the presence of demons and angels. Nor does it say in RoP:tI (that I remember) that possessing demons are sufficiently evil to totally erase the "normal grey" of human. So you are left with a "that man is almost totally evil" comment. Up to you to decide that it is a possessing demon or a very evil man. The RP will need to check here, not the GP.

That's not the question (sensing the room sense what's inside; i leave for the SG the question wether a room spell can affect a second room in the first one. Normally no, because a second room inside a first room would mean that the first room is some kind of squared hallway)). If your magi/covenant is paranoid enough to cast "anti might pool" spells on a regular basis on each room of their covenant, fine by me. But in that case, the demons have already won because pride (of being geniuses to have thought about that) is a sin you are committing.

Besides, you will banish that possessing demon part. Now he knows, and will just ask his host to never go to rooms where the magi are... or room big enough to exceed the normal hermetic magic parameters if your magi were dumb enough to make people gather in a small room to cast that spell.

Because in mythic Europe, I'd say demons are everywhere for the people. So you'd always be "right" in your suspicion and it is just as good as "there is air around me". Going that way allow the players to do whatever they want without really sensing the target.

"I cast a spell on the other side of the wall

  • you do not see there
  • I know but since the macguffin is not in this room anymore, seeing that that door is the sole entrance, and seeing that it is still open, I suspect my target to be in that other room."

"SG, i have the perfect anti demon solution and intend to use it to become archmgus.

  • how?
  • I'm doing my usual 5am anti possession spell. I devised a lesser device and worked 1 season on it. It it is a -5might pool, sight, structure +5 ssize), +51 penetration item. I destroy demons with up to 100 RM, and destroy 5 might pool. I was not sure that penetration would be used, but since I could invent it anyway with it, I did it to avoid the requirement to bypass aegis. Consider that after using that thing on me, I teleport in every covenants which pay me 1 vis a year, and cast it with their acceptation on every building they have.
    You said there was 297 covenants in the order, so that means 297 vis paws a year.
    Because my item sense the content of the structures, and because I affect building up to 100.000 times the normal size of 10 rooms, I can affect every building existing in ME.
    Teleporting has a CT of 1 round. 1 round to use the power, which goes off even if I have no token for the aegis and an average of 10 such structure by covenant, and 1 teleporting to another covenant.
    We said 297 covenants, let's give us 1 minute break every minute, that means 297*3 = 90minutes, for a total of 3 hours loss per day. Since I have 10 free days per season, season being 90 days long, that mean I can waste 1/9 day per day...3 hours is a bit more than24/9 hours. So let's say I do it only 5 times a week. But that's not optimal.

So after the first year, I will design 3 teleport wand lesser item (3 seasons), and pay 3 grogs to do it (1 pound each). I'll have them learn OohL to know the location of covenants. It may mean I have to pay 30 vis to have them go to 5 in OOH but whatever i'm rich.
That operation takes them 1 day in total, let's say winter solstice, so that I can be sure that every magus is certainly there for the aegis casting after meal.

Since they have nothing else to do, I ask them to teleport every day.

  • okay...

  • Oh I didn't think so long. Year 2, I ask those good teachers to teach 297 grogs more in OOHL. I will have to pay each of the 3 , 50 pounds for a teacher, with teaching 5 and great teacher. After they have taught 297 grogs (which would take what? 10 such good teachers?).

3 teleportation item with unlimited uses can be used 246010 times per day. Let's divide per 5 to encompass the loss of time (moving in and out the room etc.). It means 2880 uses per day x3. Since I only have 100 grogs to use per day, they can perfectly do it multiple tay per day. Let's say 24: one time per hour, (+- 1 per 1 minute and 12 seconds).

  • How do they come back?
  • You're right. I need 3 other teleport item which they take with them, and use to t teleport back. Only destination available: the teleportation room.
    Mission: 1 grog teleport to his target covenant. use the wand. Each and every day of the year, 1 time per hour.
    Use the wand, teleport back to covenant.
    300 grogs are divided into 4 squads of 75, which means 25 per item for a period of 6 hours. Then the next squad work.

I'm paying them 1 pound per year, which mean 1 vis pawn per 10 years, x300. That means 30 vis per year. Each year I gain 297 vis. It means bonus of 250 pure and simple.
Item will wear off you most certainly think. I know that you do. smile
So I give the labtext and 50 vis to a verditius to make 3reserve items each year.

Pro bono, I hire 300 additional grogs which I send off the road with 300 such item in the next 30 years (I can pay the verditius cost, in the same time I wond 6000 pawns) . They have the mission to use that item on each and every building they crossing in their travels. I use messengers to keep tracks. Since I have no time, I pay young Jerbiton and Flambeau magi : for 10 vis pawns, they take one season to find 50 of my men. It is a good deal for them (easy big amount of vis) and me (no time lose).
Oh and since they are already on a long term mission, I ask them to use it 10 times on each building. It takes 1 minute in place of 6 minutes, which really doesn't matter for me, but would destroy all demons might pool. Without might pool, most demons would be render useles.
Oh silly me. Next 30 years: I give all grogs a DEO wand also. One stone two birds, like we say.

  • ...
    Not in my saga."

I think the problem with that isn't the magic but the organization and assumption that such a straightforward approach would eliminate all demons. A demon can depart a covenant, leave behind a human ally who will call them back after the DEO has been cast, then possess the relatively unprotected grog. Then the grog teleports back and the demon hides out and kills the magus in their sleep. There are also some issues with the idea that by making structure larger you can affect multiple structures, but fundamentally the fact that demons are more cunning than say rats is the ultimate flaw in such a plan.

It's (a lot, my bad!) out of topic, but demons, as roleplayed in Ars (see box in RoPtI 46) are only capable of that with the expense of confidence point because:
[i]Most demons cannot do the following, except with extreme effort (and spending a Confidence Point, which not all demons have):

  • Act with forethought (lack of prudence)
  • Learn from past experiences (lack of prudence)
  • Display caution (lack of prudence)
    But yes, such idea only works with SG agreement... like every thing in Ars and any roleplaying game in fact. But outside of that, if you allow the principle, there is no reason for players not to try, which IMO is very bad for the credibility of the setting. Demons are meant as a threat, and possession is their biggest strenght because it's the only one which doesn't require direct penetration of an aegis.

I tend to ignore this as it is ludicrous if taken literally. A demon pretending to be a human can't pull down its pants before using a chamberpot, because that would be forethought (actually going to the chamberpot before "using" it would be forethought)
if they cannot learn from past experiences they are no more sentient than an automaton
if they cannot display caution they are effectively suicidal through rash behavior and the whole host of demons would have been wiped out millenua ago (Michael is descending with a fiery sword, but I'll throw caution to the wind and attack him with a toothbrush!)

of course at the same time demons can have traits which imitate these virtues which are not virtues- cowardice can substitute for caution, "demonic intuition" for forethought, and there are other ways they can learn rather than from experience, namely by stripping that learning from the mind of someone who does learn from experience...

In addition to which a demon can heed advice from a human which does have prudence.

I'm just arguing here for pleasure since I think it's fallen on the "YSMV", but when you say :

, I'd like it to be the case, but in my reading that is exactly:

which they cannot do.

IMO Demons in ars magica are mechanically powerful, but their "roleplaying" (which seems more close to the "truth" of the ME than other games - i do not contest that point, even if i'm not an expert - ) make them really weak against magi (who have wards, DEO who doesn't do anything bad to non-demons and can be made in Item which never fails or acts strangely (= no botch), even almost automated (each doorstep could be a trigger for a structure item with unlimited uses...)).

The only "not fully covered" thing is their possession which require to have some knowledge of a (badly seen) group of demon hunters, or to accept non hermetic help.