Fast casting against another wizard in Ars Magica

One of those forum conversations that leads into a brief explanation of how the game mechanics resolve magic… The Mirror of Opposition spell reverses the effect of a spell, but not the target. So a spell to hurt a person might help them instead. It is a very interesting spell because it relies on so many of the meta-magic layers in Ars Magica, primarily around Muto Vim spells, but there are compounding questions in the details.

Pyrale wrote: Another question regarding spell manipulation : Supposing I see someone starts casting, and I decide to cast a mirror of opposition on his spell. Does my spell have to pierce the caster’s defenses ?

If not, do I have a window of opportunity if the spell has no time of travel, or can I only cast it on projectiles ?

My 2c which might be dodgy… I think you can cast it on anything, and the SG gets to decide what it does.

  • First you need to use the rules for identifying what Form the spell is, because Mirror of Opposition is different for each Form, but I guess you might know if the caster had previously been shooting away with missile spells and just assume you’re correct if your perception Check failed. The Perception check isn’t going to slow down the rest.
    … Perception + Awareness + roll vs. 15 – (effect mag). If the opposing caster has silent/subtle magic/deft magic it gets a lot harder.
  • Then if you are not cooperating with the other caster (fair assumption) you need to fast-cast the MoO:(form), as per p.159 of Ars about not being able to intercept the spell quickly enough. Its basically a -10 to casting roll with 2x extra botch dice, and you need the fast-cast Mastery option for the MoO spell.
  • Then your Penetration total for your casting roll (which includes that -10 mod) must beat the other caster’s Penetration total
    (i.e. spell CT + roll – Spell level + Pen ability vs same from the other guy).
  • The rules imply that you don’t need to penetrate the caster’s parma which is great, although if they were casting a spell with Range: Personal upon themselves I’d argue that you’d also need to penetrate their Parma for it to work too (?).
  • The caster must be in range of your MoO spell too (voice), unless you’ve got a funky version or using an Intangible Tunnel and an AC.
  • I don’t know what happens if they are fast-casting a mastered spell, but I think you still could fast cast to intercept and alter it (?).
  • You can’t alter Spont spells with MuVi which is a bugger but it makes sense why.

Easy! However…

  • If the first spell was fast-cast then the second magus can fast-cast one to defend/intercept, but it should come back to speed (point made here). Essentially the magic system seeks to avoid situations where magi just fast-cast-BLAST their way through all encounters.
  • As MoO and many other Muto Vim spells do not work against Spont magic, and also typically must penetrate against the target spell, and also usually only affect half their level, not many wizards are able to Spont cast Muto Vim spells in defence. It is possible, but very unlikely.

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A thought on affecting spells with requisites, a meta-magic question for Ars Magica

An aside – How do requisites affect which spells can be affected by magic?

A question raised during the forum discussion asked if a Muto Vim effect could change a spell enough to make it no longer effected by a Perdo Vim form specific effect. e.g. A Sun duration Rego Terram effect is altered to a Rego Aquam effect at cast time – can a Perdo Vim/Terram spell affect it if it has “changed” the form it uses? Further could the same Perdo Vim spell affect only Terram spells, or can it also affect spells with a Terram Requisite?

I tend toward thinking a spell with a Tech and two Forms can be affected by either Form specific dispel effect. The unraveling affects part of the spells structure and it doesn’t really matter which form it unravels to make the spell loose it’s cohesion. This makes requisites a slight disadvantage, and implies that some part of the original spell is still there to be unraveled.

But I hold the same concept to other ways of affecting spells it also introduces an advantage to Mu effects affecting the Forms too. i.e. a Muto Vim Terram spell to alter Range up by 1 mag can be applied to any spell using Terram, either as the base form or a requisite. I don’t see adding breadth of application into Vim spells as unbalancing.

vale

MuVi spells to change the spell recipient (3 of 3)

Continued from Wizard’s Misdirection to Return Home and Wizard’s Misdirection to Receive Blessings, a variation to pass a spell to a target touched.

Wizard’s Misdirection to My Friend

Muto Vim General, R: Voice, D: Momentary, T: Individual

This spell changes the intended target of another spell, to target a person the caster of this spell is touching. If the new target is invalid then this spell has no effect. This spell must be one magnitude higher than the spell to be altered.

(Base Gen for a significant change, +2 Voice)

MuVi spells to change the spell recipient (2 of 3)

Continued from Wizard’s Misdirection to Return Home, a variation to force the spell to affect the caster of this MuVi spell.

Wizard’s Misdirection to Receive Blessings

Muto Vim General, R: Voice, D: Momentary, T: Individual

This spell changes the intended target of another spell, to target the caster of this spell. If the new target is invalid then this spell has no effect. This spell must be one magnitude higher than the spell to be altered.

(Base Gen for a significant change, +2 Voice)

 

MuVi spells to change the spell recipient (1 of 3)

I’m pondering the chaos of Muto Vim spells again, and all sorts of silly stuff is fluttering by my mind’s eye. As MuVi effect must have a very specific intent and effect, I’ve written three variants on the theme for changing the intended specific target, but not the Hermetic Target type. I did especially so that the three variants are (hopefully) clearly written and ready to use. Although doubtful, it is possible for a Vim specialist to cast these effects spontaneously instead of fast-cast-formulaic, to affect another magi’s casting so a quick reference is handy.

Wizard’s Misdirection to Return Home

Muto Vim General, R: Voice, D: Momentary, T: Individual

This spell changes the intended target of another spell, to target the caster of that other spell. If the new target is invalid then this spell has no effect. This spell must be one magnitude higher than the spell to be altered.

(Base Gen for a significant change, +2 Voice)

What do I want from magic? I want to see magic burn. MuVi on Spont effects…

As the hail of steel rained down upon the hillside the shrieks of war peaked and drained away to whimpers. The hill was now empty of moving figures where seconds before they swarmed viciously upon each other. A lone grey-hooded woman picked her way down the hillside, stepping through the haphazard remains soldiers and weapons. She walked with purpose toward a clutch of armoured figures collapsed together on the ground.

In their centre a similarly robed old man half reclined with a spear through his midsection and open cuts peppered across his body. Blood pooled around him, soaking the earth beneath.

“Neutral you said. Neutral” he gurgled.

“Your sworn-men came for me yesterday assisted by magic. You broke our peace,” she replied sharply. “This is the outcome,” gesturing to the ring of dead soldiers around him, and the carnage beyond.

The old man’s pain permitted a half smile with sad eyes, but he couldn’t laugh.”Let’s be done then,” he groaned, looking through her and away down the hill.

The young woman bent to her knee and reached to touch her opponent with a final gesture. She drew a deep breath as her other arm began moving in inelegant gestures, their tempo different to her gobbledygook words. A moment later the old man also rasped a quick phrases of his own, one hand forming a bridge on his chest, the other touching her. He thumped his other hand to the ground. The woman screamed in surprise and frustration, her spell gone awry. His perfectly.

The old man looked on as her conjured array of short steel spines instantly surrounded her and struck home across all quarters of her body. Her body ruined with holes sunk sideways to the ground as the spines disappeared. Lifeless.

The old man smiled again and exhaled hard. A shimmer washed him head to foot as his illusion dissipated, his skin and clothes actually unmarried; except for the long spear which still sunk deep into his side and the ground behind. He reached out for her body once and missed with a grimace of pain, then again successfully touching the woman’s body which dissipated into dust.

Looking across the field he knew he had a long evening ahead to remove all the evidence of their battle.

In the blurb above the wounded Magus uses a Muto Vim spell to retarget the spell on another – changing the range to Personal. I took a license with the concept just to have a story introduction to meta-magic post.

A fair and reasonable game balance rule in Ars Magica is for a MuVi spell to not be able to affect a Spont spell, which is why in the story blurb above the young woman casts her spell longer than the old man – hers is a formulaic spell, and his a spontaneous one. In Ars Magica’s RAW her spell could only be formulaic as spontaneous effects can’t be altered.

In-game it’s dangerous, “too chaotic and the caster will loose control“. Out-of-game the limitation is there so that Spont magic does not get trivialised (boosted, sustained, or empowered) by assistance from a Muto Vim expert.

There is also an out-of-game consideration that altering a spontaneous spell with Muto Vim is terribly inefficient way to scale up a spontaneous spell, unless the caster of the MuVi is a specialist and also cooperating with the other caster.

However in-game what if it was allowed via a breakthrough? If we take the spell guidelines as written what would happen when a Magus starts working on a magical breakthrough to find a Muto Vim discovery for spontaneous magic?

  • The SG might say the breakthrough theme just isn’t going to work, which is totally reasonable.
  • It might not work as intended but be a great story thread for the game; as it’s a great theme for an NPC wizard in Ars Magica.
  • Or perhaps it allows a MuVi based chaos effect which deliberately hooks into the randomness of Spontaneous magic. Similar to deliberately ruining a magical experiment to see what happens, it ruins both spells.
  • Or an additional rule-set is created for Muto Vim in these circumstances? And/Or it’s allowed but the penalties for botching are horrific?
  • Or allow it. Yes, it took the wizard some 30+ in-game years to develop, but they’ve cracked part of the Hermetic puzzle. It’s a huge thing for game balance, but has legs for high powered sagas.
  • Perhaps this is what all the House Diedne brouhaha was about?
  • Perhaps the breakthrough does not allow Muto Vim to alter the target spell in a predictable way, but does force the Spont spell to be chaotic – it might have an effect which is undesirable for both the caster of the Spont and the caster of the suCcessful MuVi effect?

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Suppressing the magic of others, a meta-magic question for Ars Magica

An aside I pondered a while ago – how hard is it to suppress the magic of others?

The effect from the core rulebook called Suppressing the Wizard’s Handiwork uses the Rego Vim guideline for a caster’s own spells and lasts only while the caster concentrates. It is an excellent example of a core spell designed to inspire variations. From that inspiration, here is a variant designed to suspend the spells of others.

Suppressing the Conjurer’s Incantation

Rego Vim (Gen), R: Voice, D: Concentration, T: Ind

Suspends a spell cast by another, less than or equal to Half (Vim spell level -1 magnitude) of this spell.

(Base to suppress spells cast by another, equal to half (level +5 mag) of the Vim spell, +2 R to Voice)

It illustrates that suspending the spells of others is very difficult, even more so if this effect was redesigned to extend to Sun duration; effectively suspending effects of less than or equal to half of (level -3 mags). Meaning the spell must be at level 25 and will only neutralise spells of level 5 or less – not worth it at all when compared to how easily a Wind of Mundane Silence can remove effects.

As with many things, it is easier to destroy than change or maintain. Interesting.