Complexity in Muto based Materials Manipulation

This post is more meta-magic system thoughts for ars magica –  on the complexity in Muto based materials creation and manipulation, raised from a forum discussion…

Switching one form to another should include a degree of flexibility in the final shape, as this is the declared purpose of the spell. As long as the spell is creating a specific object or thing. Surrounding air to a natural plant is fine and declaring the type and shape of the plant is reasonable in the Formulaic formula at base.

Then modifying for complexity in shape seems appropriate, as:

  • I see the complexity as quasi- geometric shapes (+0 mags) like lines, cubes, boxes, or walls. Exploiting a feature of the new material should be free too – like using a plant to create a natural shelter.
  • The allowing sub-shapes in the main shape (1) like windows, basic stairs, spikes.
  • Then almost any other ordinary detail (2).
  • Then finally very ornate details as (3) like artwork.

Having the additional mags should allow forgiveness in the Finesse check but not remove a basic “fit for purpose” check. A serviceable but ugly level for a simple item is vs 6 (a sword), and a more complex item is vs 9 (a suit of armor). Less than this and the finesse check might still be needed (vs 3) , but is really at the “don’t botch” level (a cube of stone).

So a basic sword is +1, and a full suit of armour might be +2. Then add mags for moderate flexibility in choice of form when casting. Making a spell which can pick when cast from a dagger, knife, or sword should cost something, whereas two different styles of swords which are serviceable seems plausible as a spell without too much added complexity. Sword vs axe should definetly need complexity modifiers, if not be allowed at all.

Ref: Atlas Games – Ars Magica forums.

And perhaps interrelated is the Creo vs Muto discussion here, or replacing Finesse with magnitudes of difficulty

Fire to bubbles

Substitute Finesse checks with complexity modifiers?

Discussion post – Is it reasonable to add magnitudes into Ars Magica spell designs which substitutes Finesse rolls with complexity modifiers?

By RAW no. However as a house-rule it has merit and also is sort of implied by the core rules before all the expansion rules were added. Playing Ars Magica with Core Only is very different from using all the new rules. In fact playing with all the rules would be mind boggling, so a few more choices to suit how players might want to play isn’t breaking. YSMV.

In the base rule book the Finesse skill is not given the same degree of importance to Creo and Rego magic, specifically because new guidelines were introduced in other books. 

As example – A Rego specialist Magus could be designed with a moderate Finesse in core, but would be next to useless in the expanded (now very RAW cannon) Finesse rules; primarily because the target numbers for Rego crafting magic and by extension Creo magic are ridiculously high.

How high? Well a Finesse check in the mid-20s isn’t uncommon, and 30+ is needed for the really cool stuff. In a game with 1d10+skill(1-6)+stat(1-5) that’s punitive.

I previously wrote about using time as a mitigation for Finesse checks for Creo ritual spells, and I think the suggestion makes sense. Essentially it allows a high degree of preparation to mitigate the Finesse roll, as long as the spell also has a complexity modifier built in (just as Conjuring the Mystic Tower has, which was a spell written before the expanded Finesse rules). This allows a way to rationalise the rules where one ritual spell does not require a Finesse roll, but the instant Rego/Crafting spells still do.

So what about expanding that house-rule to allow additional mags to add a bonus to the Finesse check?

Suggested new Guideline:


Caster gains +3 bonus to the Finesse check for each Magnitude added for Finesse Complexity in spell design. This complexity may only be added where the description also produces a higher quality and beauty item, and must produce a more specific result for each step in magnitude.

I’m a supporter of this principal too, as I see spell complexity as a representation of increasing detail mandated in a spell (as if the spell is an architectural design or a script).

I also like the idea that magic can have many ways to do the same thing, and a spell designer could build knowing that their version of a spell is far higher than another wizards, but they get to an almost identical result.

Along with that Finesse check should be a restriction on the purpose of the spell. A Creo spell to create a sword could have a lot of variety in the result. A ritual using this suggestion to create an ornate and wonderfully crafted sword should note what the additional complexity is for.

This ensure that the complexity added for component parts, or high detail is different from the “complexity for Finesse replacement”.

Quoting from and E.g. from the Atlas Forums by Virgileso:

Echo of Durendal

CrTe 40, R: Touch D: Momentary T: Individual

This spell creates an excellent quality steel longsword, granting the wielder a +4 Attack & Defense in combat due to its uncanny craftsmanship.

(Base 5, +1 Touch, +6 complexity)


Designer’s Notes: Rather than requiring a Finesse check against an EF 30 for such a sword, I am instead obliviating the roll altogether and setting the spell’s crafting total to a flat 12+(3*complexity) against an EF as per the Rego Craft Magic guidelines set forth in Covenants.

I don’t think it’s game breaking. My interpretation of the spell above would be that it will create an identical weapon each time it is cast because the design adds 6 magnitudes for the Finesse bonus.

It is a different style of solution to adding time (above), and while it’s plausible that these options might be used in combination a table of players would probably need to pre-select if either option was allowed and carry that forward in their games.

Happy games folks.

House rule to Mitigate High Finesse Target Numbers

High target numbers for Finesse checks frustrate me in Ars Magica, the required target numbers are borderline ridiculous for a typical wizard, and I see them as a game mechanic seeking to limit the use of certain styles of magic. They should be a way to add depth and risk to an activity, not punish players.

In a previous post about extensions to the Conjuring the Mystic Tower spell I commented about the blisteringly high finesse checks which were introduced in the Covenants and later source books. When talking about casting CtMT:

It has some issues in the expanded game, when the Finesse rolls required are extrapolated upon in additional rulebooks, so that it may (depending on the troupe) have a very high finesse check to perform, and with that the risk of a total waste of vis if the Tower is malformed. And a somewhat troubling clean-up task too.

I am an advocate of hand-waving away almost all those aspects given how infrequently the spell would be cast in a typical game, and how fundamental to a covenant’s growth the effect is.

Not to say that a botched spell or flawed finesse roll couldn’t present an intriguing opportunity…

I stand by the point that Conjuring the Mystic Tower was never intended (when first written) to require a Finesse check of 24+. It is implausible for an NPC and frankly a waste of XP for a player character.

For non-rituals, then sure roll Finesse – I accept that a little more. However any time a caster has the time to stop and plan the way an effect will be brought into being, then they should be able to greatly reduce their risk of failing that roll.

Perhaps the guide should be a +1 to the Finesse check for each day the caster spends working on how the spell will be cast. If that approach isn’t punishing enough then use the pyramid scale from XP to require a massive amount of days to be spent to “buy” the finesse roll bonus.

Fixing my Creo effects

After some banter in a game of Ars Magica RPG I’ve been corrected in my understanding of how Creo magic works. Till now I thought that Creo spells never required a Finesse skill check to cast, unless they were creating a very specific item to the caster’s desire.

Particularly I thought any natural item will always be fine, and if that Finesse check passes for an unnatural thing the item should be fit for purpose (with the natural vs unnatural thing being very generous). I thought the Finesse roll was almost always required by Rego spells which emulate crafting activity, because the Rego activity is constructing the item rather than conjuring it fully formed. Thus I was wrong that Creo only really needed Finesse rolls for style, appearance, or presentation of an item.

The core rules state that Creo effects must use a Finesse check if the thing conjured is artificial. Further if the Finesse check botches then the item is not fit-for-purpose. As a guideline it does not provide much more than that.

(the Theory of Forms only has room for natural things? A shame to miss the humble chair)
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A spell to practice Finesse or Concentration

From a question I asked on the Ars Magica forums, on how Magi might proactive their Finesse skill without taking risks with powerful magic. The simple answer which I think most saga use is that the Magus sits there using very low power magic effects to spin rocks or some such. If that is the case it is probably only going to offer the most basic level of practice, and the Magus is probably not being challenged enough.

There is also the likelihood in a “real-ish” game that the character may do themselves some damage if they botch the casting or the finesse roll badly. There is a degree of risk using control magic to spin rocks, and not really having full control.

I thought maybe a solution might be created which allowed a higher level of challenge, didn’t depend on others (such as the Bellum game which allows for fighting between magically controlled illusions, from the Apprentices source-book), and removed the risk of damaging the caster.

  • Base effect: Creo Imaginem 1 (create an image that affects one sense, p144 ArM core)
  • Modifiers for Range: to Touch (+1), Duration: to Conc (+1), Target: Individual (+0)
  • Rationale: A moving image (+1), directed by use (+1), which is increasingly complex (+1). Which is also seeking to hamper or avoid the caster’s intent (+1).
  • Final effect level: CrIm 15.

As written up as a spell:

Mastery of Thought and Purpose

Creo Imagonem 15, R: Touch, D: Conc, T: Ind

When the spell is cast an abstract image forms in front of the caster which they may manipulate using Finesse rolls, while making Concentration rolls. The spell presents a detailed changing image, which tries to resist and contradict the alterations of the caster. Slowly as time progresses the image changes more quickly, and the caster is challenged with controlling the spell for as long as possible.

Unlike practice using normal spells requiring concentration and finesse, this spell is designed to frustrate and challenge the caster. This grants a source quality of 5 for practicing the Finesse and Concentration abilities.

(Base 1 to create an image that affects one sense, R: to Touch +1, D: to Conc +1, moving image +1, directed by use +1, which is increasingly complex +1, seeking to hamper or avoid the caster’s intent +1)

The spell may also be a useful candidate for learning to multi-cast, given the concentration required.

The spell is superfluous to almost all games, where normally a player will say their characters are practicing. I wanted to supply a reasonable answer for how they were practicing.