Shield Spells

Do any of you have a favorite way to create magical shields to protect your magus from incoming projectiles? Anything along the lines of physically blocking them instead of repelling them with Rego is what I'm interested in.

I'm just curious to see how you (and your magi) approach spell design creatively.

Using spells based on ArM5 p.136 Shriek of the Impending Shafts might not be creative - but surely is very effective.

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Creo Form is your best bet if you want to avoid Rego.

Our Terram specialist likes to spont fastcast CrTe "walls" to block attacks. Base 3, T/M/I, Size +1 throws up a barrier that can stop any attack with a Level 5 spont. It is low enough level that many Magi can do it non-fatiguing. It is also large enough to protect people behind you.

Creo Herbam could do the exact same thing as Terram with the same casting totals for a wall of living wood. While wood is not as tough as stone, you are still looking at a 2x5 pace wall that is a pace thick. Very few attacks will get through that.

You could do the same with Creo Aquam (Base 4, but do not need Size +1) and it would also be able to protect others. While not quiet as effective as stone or wood, a wall of water will stop most attacks. It would actually be more effective against fire attacks and has five times the total cubic paces of material so can be much larger.

Creo Auram can be used, though it tends to be limited to attacks from a single direction rather than the potential 360 shield of Terram and Aquam. However it does have the advantage of possibly throwing the attackers back (especially at Base 5 "hurricane force wind -or- tornado").

Ignem is not very useful here, but most Ignem specialist also have a high Creo so they could use it with one of their other Forms and add a Ignem "Cosmetic Feature".

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Or perdo, though it might need to link to intelligo to target the incoming attack.

Halt the Piercing Shafts (ReHe(Te) 25) from MoH p.50.

Circular Wall of Shields (ReTe 30) from MoH p.50.


Creo vs Perdo leads to some interesting comparisons when used defensively. While I favor Creo for defense there are several cases in which Perdo is better.

Creo tends to be easier to spont (same/lower Base and less range in most Forms), effective against multiple attacks easier (by its very nature of creating a barrier vs destroying the attack), and not having to worry about the Form of the attack.

Perdo does not just stop the attack but destroys it (such as making a warriors sword suddenly disintegrate), is normally employed at range, and has arguably a much better aesthetic (rather than throwing up a shield, you wave your hand and the attack is not just stopped but gone). It can also be used as an attack in combination with defense, such as blinding the target.

Because of the general ease of the Creo defenses, they would most likely be the most common used. This would make Perdo both less expected and more impressive.

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While I agree, I do believe @Chad wanted to avoid Rego :-/

Do you require a finesse roll?
You are using instantaneous as the duration, so if you time it wrong; wall of wood blinks in, blinks out, arrow still gets target.

Sorry but a Moment is not instantaneous. We can ignore the medieval 40 seconds. Modernly it is an ambiguously short length of time. If someone ask you to "Give them a moment to finish this" do you instantly expect them do be done? A Moment can easily last a whole round and if you ask nicely @callen might actually give you a few spells/effects that do.

Well, Circular Wall of Shields is physically blocking them, while using Rego. I know the other doesn't, but I included it anyway because those two are my favorites.

Yes, there are many spells in the core book (e.g. every Momentary MuVi spell, though there are plenty more) that last a full round. There are even a few that last a little longer than a round, though far fewer of those. Momentary = Instantaneous is a common mistake.

I don't actually want to avoid Rego. That is indeed one of my magus's better Arts at present. Just for creativity's sake, though, I would like to see as many non-Rego examples of defensive spells as folk are willing to provide.

That said, I do believe that I've landed on a way to approximate a Harry Dresden shield spell via exactly that, Rego Herbam (Terram and probably Corpus and Animal as well). Range: Reach, Target: Group, Duration: either Diameter or Concentration. With a description of the "shield"'s shape that gives a case specific modification to Target: Group's relation to space.

Please, though, if you have a creative non-Rego spell that serves to block mundane attacks, do share. I love seeing creative applications of the Ars Magica spell design system, regardless of edition base.


MuAu (maybe Te requisit) to change the property of a section of air (target part) so that it does not permit movement through it

This is an option I'd been considering as well.

I've also considered Muto Auram as an alternative to "chi magic" balls of energy since ArM doesn't really have a pure "energy" attack like you see in many movies, TV shows, novels, and RPG systems.

I have already written a few house rule spell guidelines to make this sort of effect available in our saga along with some other odd Auram effects:

Why not stick with the guideline from the core book for three of those?

General: Transform air into a gas doing +level damage.

For the remaining one, depending on how natural, the core book already has level 5 and level 10 bases.

I expect a shield of solid air would be base 10 (wholly unnatural) with target part and voice range, though touch range and concentration duration could make for a "suit of armor" approach... then you just need a vim spell to maintain it.

Air with the viscosity of stone...

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The water-ice mage in my last game reacted to everything dangerous with Creo Aquam fast-cast walls of ice or unnatural gelatinous water walls to incoming attacks.


Honestly, I either overlooked it or (more likely) felt it wasn't obvious how many ways it might be applied. Maybe due to the word "gas". Perhaps for my modern mind "state" would have been more obvious.

Good outcome from sharing that snip, though. I see that my posted outlines are not consistent with each other. The first level 5 should probably be level 4 and the other three should probably be replaced with a General guideline "capable of inflicting/Soaking +Level damage" as a compliment to the canon guideline.

I saw an interesting defensive spell in a movie since last posting to this thread. Since we don't have spoiler tags that I can see, I won't name the source. Not precisely a shield, but a very creative Rego based defense.

In melee, to defend against an incoming attack, a "magus" created two portals, both with the open side facing the attacker. Portal A intercepted the attack, which immediately emerged from Portal B, striking the original attacker.

In game terms, I think this would be Re (In) Te (An, Co, He), Range: Reach, Duration: Momentary, Target: Individual. Without checking my books I'd guess level 25 in 4th.

Yes, I saw that. The existing effect it's most akin to is Hermes / Mercere Portal since anything could pass through those portals. The Ritual nature is a problem for fast-casting it. However, you could probably manage it, including fast-casting it, by using Glamour.

ArM isn't super happy about portals, generally. But if what you want is just redirection of a hostile spell onto another target (eg. the caster), that's pretty much an example of what you can do as a 'Significant change' with MuVi (see the box ArM5, p. 159).

I've also seen it argued as doable with ReVi, though I'm less certain about that one.