Spell deflection returns


I was dabbling with what was discussed in this thread [url]https://forum.atlas-games.com/t/spell-deflection/11870/1]

In this thread a spell was proposed to change the target of an hostile spell. A generic version working for all forms was proposed, but reading wizard reach (which uses the same guideline), it seems that a version should be invented for each of the hermetic forms. Am I mistaken?

There is no clear-cut answer about when a Form-specific MuVi spell is needed to my knowledge. The core canon spells that don't have to be Form specific are spells like Shroud Magic, Wizards' Communion, and The Sorcerer's Fork. The last one, the Sorcerer's Fork, really messes with me when I try to figure out the patter that determines the need to be Form specific. Of the Form-specific spells, Passing the Reins of (Form) similarly messes with me. Without those, I would have gone with changing a parameter (anything of R/T/D or that shows up in the parenthetical note) requires a Form-specific spell while other things don't. But those two spells go against this.

As for your specific one, take a look at The Sorcerer's Fork. You get to choose targets not otherwise choosable with the normal spells. This seems to be the closest to retargeting that we have among canon spells to my knowledge. It isn't Form specific, so it's likely you wouldn't need a Form-specific spell. But no guarantees here.

I'm very much interested in metamagic, and following the link tot he other thread I saw I had actually also answered that back then.

There are differences regarding 'uravelilng (Perdo VIm) and *deflecting/suppressing' (Rego Vim) in the guidelines compared to changing.

The unravelling and suppressing have both a generic guideline, affecting half of mag+4 of target spells as well as a specific version affecting mag+4.
Generic version is like Winds of Mundane Silence. Specific version is like Unravelling the Fabric of [Form] and needs to specifiy both tradition and Form/type

But magic to change magic (Muto) works differently. Guidelines speak of *superficial * , significant, and total changes.I'll focus on the significant changes, thie guideline affects spells up to mag+1. Using the most common parameters of Voice/Mom/Ind means the +2 mags for Voice causes spells like this to affect mag-1 spells.
This is in line with "Wizard's Boost" and the variants hereof. However these example spells are Form specific - not something the guideline mentions!
And quite importantly - and mentioned earlier in the thread - Sorcerer's Fork does not need to the Form specific!

So, if I want a spell to make the significant change of changing the target (small "t") of a spell cast to affect someone/-thing else (may even the caster?), and I only look at the guideline and not at any example spells I get this:

Curse the Face in the Mirror
MuVi Gen
Causes any* spell being cast, up to one magnitude lower than the MuVi spell, to affect the caster rather then the intended target**. Spell needs to be fast-cast and this spell needs to have penetration in excess of the target spell***.
(Design: Base guideline for MuVi 'significant change', +2 Voice)

*)There seems no rule in the guideline, and by extension from the example of Sorcerer's Fork, that said spell need to be specific for tradition (e.g Hermetic) or form/type!
**)Actually, there is no reason only the caster can be targeted, any legal target should do. There is no basis to demand the spell be that specific.
***) I really don't see why this is needed...or maybe I do? Because if this spell is generic rather than specific (like Perdo or Rego spells often are, in order to use a guideline equivalent in power to this) this sort of balances things out.

Exampli Gratia: Defences against a Ball of Abysmal Fire lvl 35:

A spell to specifically Unravel Hermetic Ignem needs to be level 25 to be sure to work (affecting level+2 mags+stress die), or 20 on average roll.
A spell to Unravel this , and anything else level 35 generically needs to be level 60 (affecting half of [level+2 mags+stress di]) to be sure to work, or 55 on average roll

A spell to deflect specifically Hermetic Ignem spells needs to be level 25 to be sure to work (affecting level+2 mags), no dice are involved. Example spells in HoH:Soc p129 used, except I use +2 mags rather than +10. Also, if the guideline says level+2 mags (or +10) then were to I "apy" for the +2 mags for Voice? Is there a mistake here?
A spell to deflect this, and anything else level 35 generically needs to be level 55 (affecting half of [level+3 mags]), no dice are involved. This guideline is actual in ArM5 ReVi guidelines, stating half of level+5 mags, compensated for +2 mags for Voice.

But a Muto VIm spell to affect any spell, sending it at another target needs to be level 30 (affecting level+1 mag, but compensated with the +2 for Voice). However Penetration needs to exceed that of the target spell. So while you need a spell of roughly half the level when compared to Perdo or Rego, you need a much higher Casting total. So Re/Pe needs to cast level 55-60+ spells, with Penetration irelevant and Muto needs to cast level 30 with a suitable Penetration so maybe they need the same range of Casting totals?

Also, some references say "with a level less than" but as Errata changes this to "equal to or less than" that is what I calculate with.

In the text preceeding the general guidelines, which covers all MuVi magic, you have:

So other traditions or sources of magic are explicitly excluded: there is no way to invent MuVi spells for them, and even Pralicians (HoH:S p.126ff) don't have any such spells listed.

Could Pralicians succeed in a Breakthough to Muto at least those non-Hermetic magics they succeeded to comprehend with HoH:S p.128f Comprehend Magic before?


Ah, good catch.
Refering to the Pralicians it still doesn't make sense that their Rebuttal Mastery applies to spells affecting spells or powers used onsomeone else. Specifically not Wizard's Boost effects on own spells, but on others. Also, Comprehend Magic allows one to add this Ability in Spontaneous Casting Totals of Muto, Perdo or Rego Vim used against an object or creature previously observed (for 3+ rounds). So while there are no new or further explained guidelines or examples about Muto Vim, several sources point to Pralicians being able to. And even flavour text: Page 129 "Other magical interests" refer in line 4 to "altering...shapeshifting magic, curse magic etc".

The overall magical theory does not explain why Perdo and Rego can be used on non-Hermetic magic when Muto can't. Perdo and Rego Vim is just more effective if specific rather than generic, but requires one to be familiar with any exotic traditions specified. No rules tell us what constitutes "being familiar". PeVi guidelines ArM5 p160 say: "A magus must have some knowledge of a type of magic (although not necessarily ability to use it)". Does one need to possess the relevant Hedge-Magic Theory? I don't think so, because some traditions have no Magic Theory, and no creature powers fall under that umbrella. Will study of exotic magic or powers using Comprehend Magic do the trick? Quite possibly, but is it exclusively this supernatural ability which can do this? What about Intellego Vim magic, using spells with extra magnitudes for further detail?

As stated above, I think they maybe already have!

This makes sense: both for the overall concept of Pralicians, and to get some Hermetic specialists able to Muto magic from traditions defined after the core book. It would still require an erratum of the core book, to keep the relevant texts consistent.

I should think, that

gives a sufficient explanation.
Expanding it a little: Rego and Perdo Vim affect a spell from the outside and typically after it was worked, but Muto Vim exclusively affects it while it is worked, and messes with the way it is worked - so it requires that the caster really knows in detail the processes he is interfering with.


I'll buy that.
Using Perdo or Rego Vim on an incoming spell requires little precision and more brute force, and timing I guess. If just one of many possible magical elements of the spell is ruined or twisted it fails to have the desired effect and therefor fails.
But using Muto to change a spell into doing something specific and precise requires a lot more.

So maybe a Pralician can develop and use Muto Vim spells as discussed, but can he teach them or write useful lab texts to others? I'll have to go and re-read Breakthrough and Integration. IIRC there is some example of how the first stage in Breakthrough/Integration is knowing how to use it yourself and teach it, and the second stage is to make it usable by all other Hermetic magi. Or maybe I'm not remembering it right.

It depends on the size of the breakthrough. Minor Breakthroughs are immediately understandable by other magi. You can design spells that they can directly use.

Bigger breakthroughs require virtues and initiation to use.

I think that should be minor.

A magus would have to observe magic with the Pralician Comprehend Magic (HoH:S p.128f) for three rounds, before he could Fast Cast a MuVi spell obtained with the Breakthrough onto that kind of magic successfully.
For such a magus, the Breakthrough consists in reorganizing MuVi spells, so they replace the Hermetic understanding of the target magic with the information he gathered on that kind of magic from Comprehend Magic.

So I should think, that the Breakthrough is a minor one for Pralicians and easy to communicate within that tradition - but utterly incomprehensible for all those Hermetic magi who were not taught Comprehend Magic by a Pralician before.