I just read the Ars5 errata & I did not see it there so I guess it is just that I do not understand...

Here is the problem. In the core book, CrVi spells like shell of opaque mysteries & another are momentary rituals that prevent the investigation of the target.

My undertanding of the rules would suggest that that effect needs sustainance & would hence require a duration of atleast sun to have any effect.

Do I make Sence?


Do you mean by "needs sustenance", that the effect of such a spell is "not natural" in the sense of ArM5 p.78 (Muto description), hence should not be Creo but Muto magic, hence its effects cannot remain if the spell's duration runs out?

Or do you mean, that a CrCo healing or CrTe object creation ritual of Mom duration after being cast is no longer detected by InVi spells cast on the healed person or created object, and so the CrVi rituals should neither?

Kind regards,


Partially. I Believe that the 'Not natural' applies to all techniques & not just Muto. Hence if you render someone invisible thru a PeIm momentary ritual, that person would only be invisible for a faction of a second since it is not natural for him to be invisible. It still remains PeIm & not MuIm.

In the example that I gave, the ritual give a magical property(Not natural) to a target. The effect is set to a momentary duration. The duration of theeffect according to me would be that it would last but a moment.

Well they would all leave traces of magic as usual. CrCo healing is 'natural' for some reason & creatin a mundane object is natural also. Basically, for the same reason that if you create a object that is 'Not natual' thru a CrTe ritual, you need to set a duration for it, the CrVi ritual which creates an unnatural shell, should have a duration set also.

Is it clearer?


For me, yes. So, your argument is, that a magical property can never be natural, and hence the effect of Shell of False Determinations (SoFD) or Shell of Opaque Mysteries (SoOM) cannot remain once the D:Mom of these rituals has run out.
It is not 100% clear from their phrasing whether SoFD or SoOM can be cast on non-magical items, too - making them fake magic items resisting investigation. But if SoFD or SoOM is cast on magic items, one could argue that these items anyway appear magical if investigated, so adding to the magical information (SoFD) or noise (SoOM) found is adding to a now natural - and anyway already sustained - property.
This means distinguishing between 'mundane' and 'natural', of course. If one does not do so, CrVi rituals do indeed not make sense.

Kind regards,


Those spells are Creo rituals right? There are special rules which aplies to Creo rituals, they are the only kind of spells which can be made permanent with the use of vis of course.
The only problem I see is that the result of Creo rituals are per definition non magical, but with CreoVim rituals - how can the result be non magical? A bit of a contradiction?

Essential nature is the problem here. SoFD & SoOM both target a mundane thing that is under a magical effect(or possibly not). SoFD & SoOM both go against the essentail nature of the target which is to be investigated without restriction. Hence the effect should be sustained by magic & cannot be a momentory duration ritual spell.

I think the rule book just uses Cr Ritual to show to explain how you can have a 'permanent' effect that does not go against the Law of Essential Nature.


Essential nature by ArM5 p.79 cannot be changed by Hermetic magic, any Hermetic magic violating it must always be maintained. So far, so well.

But when an item is enchanted without charges or Effect Expiry, it changes from being mundane to registering as magical - forever until disenchanted, and without being maintained. Since enchanting an item is Hermetic magic, this change then obviously cannot be a change of the item's essential nature.

So also SoOM and SoFD would not violate essential nature when changing how an item registers when investigated in a Hermetic lab.

Kind regards,


In these cases, the magic is sustained by vis. The essential nature still remains mundane. Take out the vis (read disenchant) and the item is back to its essential mundane naure.

I dont follow you here...

The employment of Vis in ArM5 cannot maintain an effect violating essential nature indefinitely. Otherwise also Muto spells could be maintained by Vis in D:Mom rituals indefinitely, which clearly is not the case.

Kind regards,


You need to remember that invested devices are a breakthru that was intergrated to hermetic magic by Bonisagus & Verditius.

A pawn of vis will remain magical untill consumed. The breakthru technique of fusing the vis with mundane object allows hermetic mages to place magical effects into a medium 'permanently' but the essential nature of the object is still mundane. The breakthru jus allows us to bend the law of essential nature for a bit longer that usual.

So you claim that that the Limit on Hermetic magic of Essential Nature was already 'bent' by employing Vis before Hermetic magic was even codified? Not by rituals using Vis, but by enchanting items using Vis? And that item enchantment - gotten into Hermetic magic through Verditius with some help of Bonisagus - is a breakthrough, while a ritual using Vis - gotten into Hermetic magic through the Mercurians and Bonisagus - is not?

ArM5 p.79: "Most Hermetic theorists believe that there are only two fundamental limits, the Limit of the Divine and the Limit of Essential Nature, and that the other limits are derived from one or other of these. ... The boundaries of Hermetic magic are well known to the Order, but that doesn't stop magi from challenging them. Indeed, many magi spend countless years searching in vain for a way to transcend these limits. Certainly, any magus who actually succeeds in doing so will become famous, perhaps as famous as the Order's very Founders."

HoH-TL p. 27: "A Hermetic Breakthrough is a new Arcane Ability or the breaking of a Lesser Limit. ... In a canonical Ars Magica setting, the Parma Magica is the only Hermetic Breakthrough that has occurred in the 450 years of the Order of Hermes."

Would in your campaign a magus who by incredible perseverance, luck, serendipity and perhaps supernatural (SG) help got around the Limit of Essential Nature, thereby achieving something well beyond a Hermetic Breakthrough, will just be pointed to Bonisagus, who already had provided a means of permanently changing an item's essential nature which just uses Vis and a few seasons?

You would not expect your interpretation of essential nature to go into errata, though, would you?

Wouldn't it be far more in keeping with the ArM setting to conclude, that it is not part of an item's essential nature whether and how it registers when investigated for magical properties by Hermetic magic?

Kind regards,


I do not think so.

For the same reason that beeing invisible is not part of the essential nature of a natural item, the fact that it becomes invisible to the eye of an hermetic spell or investigation by the use of a CrVi ritual is also against its essential nature. Saying otherwise would mean that the item could naturally not be investigated by magic.

This is way I believe that both SoFD & SoOM should be of a duration greater than Mom to have any noticable effects.

As for the other comments you made. I think that it is well know that before the order was created, some wizards were able (some still are) to do things that bend the hermetic limits. With fey magic you can get longer duration / heal without vis. Divine magic can also do special things. The current setting allows for a lot. Investing devices is a breaktru that allows to go around the limit of essential nature to some limit. Hearth beast also goes against the essential nature limit if you think about it.

My point was that even if an invested device will sustain indefinetively magic until dispelled, its essential nature is still a simple mundane object.

I don't see the invisibility analogy: a magical item under SoFD or SoOM does not become invisible to magical analysis - just inscrutable or registering with other powers.

By canon there is no way to go around the Limit of Essential Nature, and I already gave you the ArM quotes for it. Even the HoH-TL Original Research rules have no provision for getting around this limit. (Though campaign specific discoveries at storyguide decision can of course circumvent that.)

A heartbeast is part of a Bjornaer's essential nature and determines his/her personality from birth. That heartbeast is discovered, not bestowed when a Bjornaer is initiated into the Outer Mystery. So this Mystery does not violate but rather reveal essential nature.

So it is your opinion now, that an enchanted item's magical properties are not part of that item's essential nature. I agree to that. From this we conclude that whether and how an enchanted item displays these magical properties can also not be part of its essential nature. And then altering how an enchanted item displays these properties under investigation can also not violate its essential nature. So the CrVi rituals SoFD & SoOM do not violate an enchanted item's essential nature.

Issue resolved and agreement reached about SoFD & SoOM, I think.

Kind regards,


I see your logic. Let us apply it elsewhere.

We have a mundane stick can can heat itself thru a CrIg spell that is invested into it. The spell is not part of its essential nature. That means that we can that have a number of momentary rituals affect the heat since it is not part of the essential nature of the stick as does SoFD & SoOM.

This is where your logic is in error I think.

"enchanted item's magical properties are not part of that item's essential nature" > True

But, it is part of the essential nature of the magical effect to be able to be investigated.

That is why I think that SoFD & SoOM sould be sustained. They go against the essential nature of the magical effect that they mask.

Not to take away from the debate, but the simple answer is that Creo Rituals of Momentary Duration are permanent.

If I read the above correctly, a magical effect not only has an essential nature, but is an essential nature. Because it is an essential nature it can not be investigated by Hermetic Magic.

I think this is an over interpretation. First, I don't think there is any evidence to suggest magical effects have an essential nature. Even if a magical effect has an essential nature that does not mean a magical effect is an essential nature. Were a magical effect an essential nature, then in addition to magical effects needing to be maintained by magic, they would be immune to all Intellego, Rego, Muto, or Perdo spells.

Tech plus Vim clearly establishes that magical effects can be controled, changed, destroyed and investigated. So magical effects can not be 'active' essential natures. It would seem to me, that magical effects are anything but the creation or alteration of an essential nature. Because of this, Duration:Momentary can change a magical effect in the same way Duration:Momentary can change a physical object, such as burning flesh and leaving a 'permanent' effect.

As I read SoFD, the 'shell' is Momentary, but the effect (per Momentary definition) "... of the spell will endure long after the spell itself finishes."

Instead of the essential nature of enchanted items, you now really wish to discuss the essential nature of Hermetic magical effects? ':shock:'
Lacking any possibility to fall back to Aristotle or medieval authorities on that subject, you only can resort to the ArM5 rule books for evidence here. The existence of SoFD and SoOM implies that it is possible and not violating its essential nature to mask a magical effect. Did you find any evidence to the contrary in the rules?

Kind regards,


Yeah, but the result should be a thing that is non magical right? A momentary Creo ritual, you spend the vis, and create something (or heal, or make something more perfector wahtever) and that thing is then nonmagical, nondispellable.
Considder theese CrVi effects. How can they be nonmagical and non dispellable.
That poses a problem as I see it.

Creo Rituals create things that last as any other thing of that type. It doesn't necessarily have to be non-magical. If the object had to be non-magical, then there would be no Creo Vim Rituals at all.

If it's a Creo Herbam Ritual to create an apple, then a nonmagical, typical apple is created.

If a Creo Vim Ritual is used to create a spell, it should create a spell that lasts as long as a typical spell of that type. A typical Creo Ritual spell is permanent. Therefore, the Creo Vim spell should create a permanent spell. Maybe the perfect spell is permanent, so the Creo Vim creates a perfect version of a spell effect?

So, could you use a Creo Vim Ritual to create a permanent version of another spell? A magical reservoir, for want of a better term, which could sustain another spell... probably would need a Rego or Muto requisite (maybe both)...