The spell "Aura of Inconsequence" ReMe25, Touch/Sun, Spec from HoH:TL, p73-74 is cast on a recipient (small "t" target) and at any point during the spell's duration´the magic becomes active when people look at the recipient, and their attention is diverted.
Should this spell even be possible in Hermetic magic? I remember discussing it with Tellus some years ago, and he was not impressed.
Such a thing seems possible with House Bjornaer's Mystery of Sensory Magic, where Target:Spectacle covers such an effect.
In 4th ed an before the spell Aura of Rightful Authority was cast on the recipient of the effect, rather than those people you wanted to command. In 5th ed it is a straight forward mind control spell, cast on the target you with to impose your dominance over. Aura of Ennobled Presence is another thing, since it actually changes how the recipient looks. It has not seen significant change through the editions.
However much I'd like to use Aura of Inconsequence is seems to be doing what other spells (e.g. AoRA) have stopped doing, since 5th ed Hermetic Magic does not support it. I know is has T: Special, but the spell somehow affects target not present at the casting, and is totally flexible because you can just walk into a city. Even the static T: Circle does not simply wait for things to enter and then affect the,. In fact, only the very non-standard Aegis of the Hearth does something like this.
So nitpicking about Hermetic Magic means this spell should not work as described.
It is, however, a lucky fluke of an inventive Guernicus incorporating research of Fenicil (HoH:TL p.39f) on magic traditions preceding the Order of Hermes, which is kept a secret by the inner council of the Quaesitores. Modifying the spell or generalizing its concepts requires access to Fenicil's collection and a major breakthrough.
Well that’s a plausible explanation, since it refers to a non Hermetic ritual.
However it only says “inspired by” and nothing denotes this spell as unique, experimental, or restricted to magi Guernicus. So. As written it merely has a Target: Special and should be possible for any magus to invent.
However it sort of undermines Spectacle of Sensory Magic. Although Sensory Magic covers many more such parameters and allows Heartbeast score to be added to lab totals.
"possible for any magus to invent": Check
"Inventing a version with different parameters requires major breakthrough": Check
I added just the need to access Fenicil's top secet research for any further extension of Aura of Inconsequence - and that appears pretty plausible to me.
For AM5.5, I recommend making Sensory Magic part of normal Hermetic Magic, no extra virtue required and obviously without Heartbeast restrictions. Then, Aura of Rightful Authority can work more the way it used to back in the day.
EDIT: I'd even recommend going a step further to generalize this kind of spell, so that we can include spells that deflect incoming arrows (non-living, so sensory magic doesn't quite apply) and ward against animals, etc.
I believe the idea of the author or editor was more or less to convey what OneShot wrote: the spell is
What would be needed to generalize the spell or its concepts, particularly in terms of level-of-effect, is ultimately a troupe decision. Though I disagree about it being necessarily a major breakthrough (see 3 below).
This is somewhat tangential, but I disagree with Christian Andersen when he writes
There are a number of other spells in the corebook that affect everything that enters an area, even after spellcasting. For example The Shrouded Glen. This was heavily discussed in the past (though I cannot easily find a pointer). In general the consensus seems to be that you can have area spells that affect all targets in the area at the time of casting for the duration of the spell, even if those targets subsequently leave the area; and spells that affect all targets that enter the area throughout the duration of the spell, even after the time of casting.
If we ignore the level and Arts of Aura of Inconsequence, in principle such an effect does not violate or even bend the rules of Hermetic magic. We certainly know that Hermetic magic can give animals magical abilities: see the MuAn25 guideline "Give an animal a “magical” ability, such as the ability to breathe fire (requires a requisite for the ability)." It seems reasonable that if we can change a toad so that it breathes fire, we can change a toad so that it gains the two powers of a) sensing attention to itself and b) making itself inconspicous in the eyes of those it senses paying attention. It also seems reasonable that a similar effect can be cast on humans instead of toads.
Accepting the thesis in 3 still leaves open a crucial question: what level and Arts are needed to give someone a magical ability? In addition to those required for the magical ability to operate (in our case Intellego, Rego, and Mentem) the "human" equivalent of MuAn is probabily MuCo, though note that granting magical senses to people is explicitly MuMe (corebook p.114) and one could think about other options too e.g. CrVi. This is very much a troupe decision, just like the determination of the base level for powerful abilities. In this sense, even if we look at the MuAn guideline, note that allowing a Base 25 guideline to grant a level 5 or 10 power seems reasonable; doing the same with a level 50 power is obviously not good design. In general, giving someone a power should be significantly harder than exerting that power yourself. It should also be harder than doing the same via Sensory magic. So, yes, definitely harder than the spell as written (and with requisites)!