Order of events
1) Danny the mage cast detect enemies on the physical plane.
2) Adam the mage uses a spirit to search out Danny
3) Adam's spirit finds Danny
4) Adam astrally projects and hovers to be with in melee range of Danny
5) Adam readies and action to smack danny with a weapon focus as soon as he is on the astral.
5) Something makes Danny pop astral projection
6) Adam takes his readied action to hit danny

So questions:
A) when does if ever does detect enemies go off.
B) How would you resolve ambush.
C) How would infiltration/Shadowing help
D) Would it make any difference if Adam stood behind Danny

I can tell you how I would rule this:
A) It doesn't because there were never any hostile intentions on the physical plane.
B) Just like any mundane ambush, initiative check with the ambusher receiving +6 dice to his roll.
C) Shadowing would not (Not with the planar devision), Infiltration usually would as it works on both sides of the 'mirror-wall', but I don't think Adam would be using it in this case as he is aiming straight to penetration and isn't pussy-footing around in any astral shadows.
D) I like to say that in any combat situation people are spinning, moving, jumping, and generally being aware in all directions. But if you want to give Adam a bonus to his ambush role for superior positioning I don't think anyone except Danny would mind.

Check out the thread somewhere around here for more about infiltration and perception on the astral plane.

It would never go off. It was cast on the physical plane, and the only aggressive presence remained Astral (unless Danny happened to be near Adam's body).


As per page 156 of the main book. Adam gets +6 initiative, and if he has a way of knowing when Danny will be forced to project, he doesn't have to check for Surprise. If he doesn't know when Danny will project, then they both check for surprise normally.


I'm not sure it would apply. For more thoughts on it, check out the thread about Concealment on the Astral.


I'd penalize Danny's Surprise Check by 3, there's a chance his astral senses might notice that something is off, and he might react in time to avoid the first attack, but I rather doubt it.

D: I might rule that Danny doesn't get a Defence check, per Defender Unaware...

Since Adam is excplicitly hanging around in melee range I´d have him roll a heavily penalized (-8ish) Shadowing test that would add to the 6-magic threshold for Danny to notice that something magical is sitting right next him in the astral. The outcome of this test determines whether Adam gets the +6 DP bonus on the surprise test when Danny goes astral.

As has been pointed out, this wouldn't normally go off. However, if Danny astrally perceived (NOT projected) I think I'd probably be willing to let the spell 'travel with him', at which point it would go off.




Adam would have surprise, so I'd roll a surprise test (reaction test vs. 4 for Adam, 6 for Danny) then proceed like normal. I'd use Danny's astral reaction for that test.



The answer is 'not likely to help' to both. Assumedly Adam is choosing an appropriate point to ambush Danny from and, well, is ambushing Danny. He already has surprise, which is his number one benefit. In theory, Adam will succeed at either the surprise and/or initiative test (especially since Danny is penalized with initiative until the next round), allowing him to hit Danny.

However...
Should Adam botch his surprise test so Danny beats him, and then Danny has enough initiative left over to actually move before the end of the round (and surprise wears off), Adam can take advantage of a Stealth check at some obscene TNs to avoid being noticed for those few turns. If he successfully avoids detection standing RIGHT BEHIND Danny (unlikely), he'll get a chance to attack when initiative is rerolled.

Keep in mind that:

A) just how long is Adam waiting in the astral? Boredom, or even the magic rating time limit could kick in if he doesn't have a way to cause Danny to expose himself. (Astral Projection p. 183)

B) shadowing is going to be important: any time his astral body passes through someone, they get a check to see if they notice it...even mundanes. A mage gets a +2 on this perception check. (Astral Detection p. 184)

Just a few thoughts and quotes on the issue:

Detect Enemies, Extended (Active, Extended Area)
Type: M Range: T Duration: S DV: (F/2) +3
The subject can detect living targets within range who have hostile intentions toward him. The spell does not detect traps (since they are not alive), nor can it detect someone about to shoot into a crowd at random (the hostility is not directed at the subject of the spell.) The spell can detect targets preparing an ambush or other surprise attack.

“A magician in the physical world can only cast spells on targets that are in the physical world. Similarly, a magician in astral space can only cast spells on targets that have an astral form (though the auras of of things in the physical world can be seen, auras alone cannot be targeted.) . . . An astral target can only be affected by mana spells—even if the magician is in the physical world astrally perceiving—as it has no physical presence.�

Mana spells affect their targets through the mana that permeates the astral and physical planes—affecting the target in a magical and spiritual manner that is only effectively resisted by the Willpower of a living or magical being. Physical spells directly target the body; resistance relies on the target's Body attribute. Only mana spells can affect astral forms. Either type of spell may be used in the physical world, but mana spells cannot affect non-living targets. (p 195)

Detection spells give the subject a new sense, beyond the normal five senses, for as long as they are maintained. They are cast upon the magician or a subject within Touch range. . . . either directional (like normal sight), area effect (work in all directions at once, like hearing), or psychic (providing some other special “sense� such as telepathy or precognition.) p197

Active: The sense actively analyzes or seeks out certain information when the subject concentrates on it. Active Detection Spells are treated as an Opposed Test, pitting the caster's Magic + Spellcasting vs. the target's Willpower (+ Counterspelling, if available), magical objects resist with Force. . . . see table . . .
Range: . . . If a caster sustains a Detection spell, new targets may be detected as they enter the range of the spell; in this case, the gamemaster simply applies the results of the original Magic + Spellcasting test to see if the new targets are noticed. p. 198



So, as a spell Type: Mana, it can affect astral entities. It's Range: Touch, indicates that the spell is cast on an individual, who then possesses an Area Effect new sense--ie. the spell is cast on a person, who then possesses a sense with a range. It's duration is Sustained, so new targets may be detected as they enter the range, with the Active component "actively" seeking out and analyzing hostile intent.

So the possible effects seem to be:
A) If the spell is cast on the physical, it stays tagged to the body, even if the Astral Form (remember, it's Mana based) it was cast on then Projects. The spell would be a good way to guard your body from people while you are out. If the spell is cast on the Astral, it would warn you if Astral threats came within range, even if you weren't astrally perceiving.
B) The spell is tagged to your Astral Form, whether it is in your body or Projects out. The caster would carry the sustained spell with him/her (makes sense given the Sustaining aspect.) When the mage shifts perception to the Astral, the sense shifts, too, actively warning of ambush (now only on the Astral), regardless of relative positioning on that plane. Perhaps it gives a bonus to the surprise roll, like Combat Sense does.
C) The spell works on both physical and astral, since it is detecting intent and is mana based.

Personally i favor B. It's a mana spell, so it affects "the target in a magical and spiritual manner" rather than "directly targeting the body." Option A would indicate a Physical spell. Option C seems a bit powerful.

Just my $0.02.

Mr. U asks: "just how long is Adam waiting in the astral? Boredom, or even the magic rating time limit could kick in if he doesn't have a way to cause Danny to expose himself. (Astral Projection p. 183)"

Most PC mages say "I look on the Astral" at the drop of a hat, and it's usually a good idea, including in many social encounters doing a quick Assense to see if the aura's mood matches the body language. So if Adam sends a watcher spirit to materialize near Danny then pop away, it's likely that Danny will look on the astral.

Danny might say "nope, I bet it's a trap, I'm staying right here on the physical." But ignoring the astral ain't safe either... what if Adam is also the spotter for a ritual magic hit squad? (Well, in that case, Danny is probably SOL.)

Assuming Danny is a conjurer, Danny might send a spirit to go check the astral vicinity first, and follow only when the spirit reports that the coast is clear. And that might be SOP if astral whackamole is a popular tactic.

Indeed, many mages have spirits with better Assensing than the mage has...

R.

Yea, I'd be a little shocked is a watcher spirit materialized since watcher spirits can't materialize.

I imagine you'd probably mean manifest since they can do that, so I'll forgive you.

Now to answer the question I would say consider the spell detect magic.



Now if someone were to suggest that detect magic can see a spirit in the astral but detect enemies cannot detect a spirit or other astral form from the physical plane then I'd want to know what basis they justify the double standard.

No, detect magic cannot detect a magical object on another plane. Read the last part of the line you pasted, 'within range of the sense'. If the sense is limited to the physical, it's still limited to the physical.

There is no justification for the definition of Range you are proposing. This is a Detection Spell and p.198 includes a definition of Range that has completely excludes any mention of planar boundaries.

It is clear from the text that you cannot target a spell across planes, however that may be creating a confusion here as Detection spells work differently in how they target. Recall that the target of a detection spell is the recipient of the new sense not the object being detected. The ability of the new sense to cross planar boundaries is unaffected by that rule.

Consider also that the very first line of the Detection Spell section on p.197 says, "Detection spells give the subject a new sense, beyond the normal five senses, for as long as they are maintained." There is clearly precedent for even normal senses crossing the astral barrier. Per p.184 Physical beings may sense when an astral form passes through their aura. See the very beginning of the Astral perception section p.182, "It [astral perception] is the primary sense used in the astral plane." It is clear that the sense astral perception can detect things across the planar barrier, you can detect objects even those without auras with a mere sense.

My first intuition on this one was, yea, spells can't cross the planar boundary and thus no detection, however as I read into it I'd say you don't have a case that there is any illegal plane crossing to detect an astral enemy with detect enemies since there is no "Targeting" across the astral which is what is prohibited. We have examples of senses that cross the planes as per above, and a detection spell is just a new sense.

My initial gut reaction was that a certain someone was going to get detected. Then the conversation went towards the separation of astral and physical. This separation in my mind really only exists in the sense of targeting. In this instance the target is the caster, not the enemy. So if I was running it someone on the astral is going to set it off, of course nothing explicitly prevents the opposite interpretation from being true, so I can easily see people ruling the other way.

I've gotta weigh in here. Since detection spells target the mage, and not the enemy, I'd say his new "detect" sense is cross-planar. Simply because the only definition of limitations given is the range. If the whatever is inside of the range, then it goes off. No distinction about planes is made, and as such, there is none.

Tarantula sums it up best for me, I agree with his reading of the spell.

WMS

Relevant sections of SR4 and SM are:

p 173 SR4 Choose the Target (stormcrow, et al)

p 163 SM



Unfortunately while SM(for detection spells) makes the distinction between target and subject, SR4 does not. But if we take the SM definition of what constitutes a subject and what is a target, and apply it to the descriptions in SR4, then we can see that the passage in SR4 with respect to Detection spells becomes:



Hence the only relevant statement left here is "An astral target can only be affected by mana spells". Since Detect Magic is a mana spell, therefore it can affect(the sense can be "used on") a astrally projecting entity.


Correct, if the sense is limited to the physical. For example, hearing is a physical sense and therefore it is limited to the physical. Detect Enemies does not have this distinction.

Actually, what I was getting at there, was the fact that just because he was located, doesn't mean he's guaranteed to go dual-natured or astral in the next (Adam's magic rating) hours...he could, for instance, be at home, asleep.

And, of course there's also the location aspect - just because a searching spirit can find someone inside a ward, doesn't mean a projecting magician gets to pass through it without alerting the ward's creator. And I've known players whose characters often stayed inside warded locations for days (or even longer, if paranoid enough) at a time.

Overall, without already knowing his target's schedule, Adam would have to be moderately lucky to have the spirit's search pay off at the proper combination of time, location, and activity to use that kind of ambush tactics. Not impossible, but hardly guaranteed.