Hello.
I've had a situation coming up in my recent games that is showing my lack of knowledge in a specific area. Long story short, my players have come to favor a tactic to stare at just about anyone they meet with detect magic (in case of illusion magic present upon them). I'll admit they have had some issues with this in the past and it makes sense they would start to get a bit paranoid.
However, it seems strange to me that a simple cantrip should be able to trip up a lot of these abilities. Several of the monsters in question are of the Oni subtype meaning they receive their shape-changing as supernatural abilities.
So finally here is my question, in what cases would detect magic register this? My guess was after some reading that supernatural and extraordinary wouldn't, but spell-like and when the spell is cast on them it would. Is this the correct interpretation? I don't want to screw anyone over but having them insta-scan everyone they meet is making me a bit leery.
Thanks for any help!
Bonus Questions: Does detect magic detect invisibility spells? Or only if the person remains standing in the same spot for the whole three rounds? Is there an 'after image' of the magic still there even if the person moves away?
Spell like and supernatural abilities are both "magical." Spell like abilities typically mimic spells so that is easy to understand, supernatural abilities are sometimes specifically written for particular creatures and don't have a school (like an aura) or if they mimic a spell have that information as per the spell.
Having the ability as an SU should trip the detect magic, when it is active. There are limitations on detect magic though. One it is a standard action to maintain concentration, as such that person isn't doing much else and anyone with experience with magic should be able to figure it out even if they didn't cast it right in front of them. Another is that it just tells you the school, not what the effect is (Know: Arcana for that, 20+DC). A third is movement, any creature will be able to break line of sight or out distance/leave the cone of someone using detect magic on them. Lastly, Non detection spells last a long time (1 hour/level) if you need a plot npc to avoid detection for prolonged periods.
Detect magic would detect an Invisibility spell as well as any magical auras on the invisible creature, however the creature bearing the invisible spell isn't in line of sight technically so they cannot detect where the aura is exactly. Basically they should know that something is there (at least 1 aura if not more) and if the creature stays in the spot for 3 rounds get the school of illusion, they however cannot pinpoint it or read other auras.
As a cantrip, giving a hint that something is odd is okay, taking the place of a spell that is higher level (detect invis) is beyond its scope.
it just tells you the school, not what the effect is (Know: Arcana for that, 20+DC).
Detect Magic tells you 1) Presence or absence of magical auras. 2) Number of different magical auras and the power of the most potent aura. 3) The strength and location of each aura.
To learn anything more than that requires checks.
To determine the school of magic, you make a Knowledge (arcana) check at DC 15 + spell level, or 15 + 1/2 caster level for a nonspell effect.
If the aura emanates from a magic item, you can attempt to identify its properties via Spellcraft.
Does detect magic detect invisibility spells?
Say a level 3 wizard has cast invisibility. Lets also say he stays still. (Doesn't want to move and make noise)
Round 1: You detect the presence of magic.
Round 2: You detect one aura, and the most powerful aura is Faint.
Round 3: You still only detect one Faint aura, but you are unable to pinpoint the source. Make a Knowledge (arcana) check to determine the school of magic. (If the player makes the DC 17 check, he learns the school is illusion)
Lets say the wizard realizes the person just cast detect magic, and is focusing in his general area.
Round 1: You detect the presence of magic.
(Wiz: Crap. Maybe he'll turn away...)
Round 2: You detect one aura, and the most powerful aura is Faint.
(Wiz: Moves (using stealth) 30' away, leaving the cone of effect)
Round 3: You detect a dim aura but are unable to pinpoint the source.
(Wiz: whew!)
in what cases would detect magic register (Sp/Su)
If it's not coming from a Functioning spell or Magic item, then according to the chart it doesn't have an aura. I think that puts Supernatural abilities in the clear. Spell-Like would probably still show up, though. (IMO) It should really be "Detect Spell" not "Detect Magic".
I don't want to screw anyone over but having them insta-scan everyone they meet is making me a bit leery.
Keep in mind many people find spellcasting to be a hostile action. If someone you don't know walks up to you and casts a spell, you're unlikely to stand there for three rounds while he does stuff. After a few people call the guards or cause a commotion, they might learn to be a bit more discreet.
Thanks! I really wasn't sure what I was missing, but I was sure it was something. The DC to know the school I hadn't taken into account. Not to mention that them doing this in a crowd of people might cause issues too. Nondetection for the more plot oriented types should also work. Great advice!
Grick, could you point me to the chart you mentioned about auras? I'd like to read that section. It sounds familiar what you said, but I can't recall where to find it.
Grick, could you point me to the chart you mentioned about auras?
Detect Magic, scroll down to the Detect Magic table.
...I can't believe I completely forgot it was written up in the spell itself. Yep, definitely feeling stupid now. >,<