Vanishing Trick / Invisible Blade vs Detect Magic

[Jagster87]

Hey folks,

I was curious in regards to how the Ninja Tricks Vanishing Trick and Invisible Blade interact with Detect Magic. As written, these abilities are stated to function as Invisibility and Greater Invisibility, so my guess is that they would still emanate some sort of magical aura and their use could be detected by Detect Magic. However, I wanted to get some input on this in case there has been something official said somewhere that I may have missed, or if anyone has a valid argument for why their use wouldn't be detected via Detect Magic.

Thanks in advance! :)

[Chess Pwn]

Detect magic can sense the presence of magic in a cone in one round. It takes 3 rounds to pinpoint the square the magic is in. If the invisible person moves out of the cone they need to start all over to try and find them.

[Entryhazard]

I'll quote Ravingdork's post from another thread

Ravingdork wrote:

The newly released Ultimate Intrigue actually addresses this.

Ultimate Intigue wrote:

Detect Magic: Though this at-will cantrip is an extremely powerful tool, remember that concentrating to maintain the spell consumes the caster’s standard action every round, and may significantly slow a party’s progress when timing is important or action is required. It also requires several rounds to reveal useful information.

On the first round of the spell, the caster doesn’t learn more than the presence or absence of magical auras in a 60-foot cone. If the wizard is standing behind someone in the party who has a magic item, he’ll get a false positive. Even on the second round, the caster just learns the number of auras and the power of the most potent aura, so it takes quite a while to pinpoint the locations of each aura. For instance, a common complaint about detect magic is that it might reveal invisible creatures, but in reality, an invisible creature can easily run circles around the concentrating wizard’s cone, never allowing the wizard
enough time to pinpoint it.

The final and most important point to note is the fact that magical areas, multiple types of magic, and stronger auras can distort or conceal weaker auras. Very few GMs use this to its full potential. For instance, the NPCs might build their base on a ley line in order to mask magic auras. If all else fails, numerous countermeasures protect against a simple detect magic spell, starting with nonmagical means such as thin layers of lead and moving to magic aura, nondetection, misdirection, and more. Take a look at greater magic aura (see page 219) for a solid countermeasure. Greater detect magic (see page 212) allows for some interesting additional pieces of information, but it’s a 2nd-level spell, so it can never be as ubiquitous as the 0-level version. Greater magic aura still foils greater detect magic.

[Claxon]

Yes, detect magic will detect the aura from invisibility, but it isn't really useful.