Penetration HR for Item Creation using Arcane Connections

In many myths and stories weapons and devices are crafted to hurt specific creatures, or a type of creature. Ars Magica does not specifically support powers meant for classes or types of opponents. Examples like the way Stormbringer from the Elric saga drinks energy, or Sting from the Lord of the Rings warns when orcs are near.

In Ars Magica items can be designed with powers to affect supernatural creatures however often these creatures will have resistance to spells and powers. As Penetration vs MR is the existing mechanic in-play to represent this I think it makes sense to provide options for Penetration which empathise the saga and story aspects of these special tools.

These are the types of proposed special options in item creation in Ars, all which modify how an item calculates its penetration score for a particular power:

  • Prescribed¬†Penetration
  • Entity¬†Penetration
  • Arcane Penetration

Note that if any of these options for additional penetration are used together their effects are not multiplicative, meaning that they modify the base amount of penetration in the enchantment, not the boosted amount.

Prescribed Penetration (+5) – Penetration of invested powers is enhanced when used with the Target for whom the AC applies, and is otherwise ineffective. The goal with this style is to prescribe the type of target and how the AC is used within the enchantment.

This adds half again the Penetration point already invested into the invested power design, however the invested power has zero penetration against other targets.

Invested powers using Prescribed Penetration must declare the material and technique of ACs which can be used and the manner in which the power interacts with the item. The method must also match thematically to the use of the power and item.

i.e. a magical sword could be given a “blood drinking” power to gain enhanced penetration against foes. That invested power could not make use of another AC which wasn’t blood.

The AC need not be “fixed” or permanent, however the AC must be physically touching the item when the power is invoked.

For example: Blood on a sword. Powers invested in a magical blade have enhanced penetration only if the wielder is able to first inflict at least a light would with the blade (or otherwise draw blood of the victim onto the blade).

Entity Penetration (+10) This option links the invested power to a fixed arcane connection to a specific individual, thing, or place. When used this enhances the penetration by doubling the invested base item penetration.

Arcane Penetration (+10) the penetration of the invested effect uses the penetration skill of the person activating the power, as per the Form + Tech + Penetration ability with all normal modifications for the arts of the invested effect rather than points invested in Penetration.

Arcane Penetration also requires that the activator also be touching the magical device when the power with this option is activated, and when a power with this modification is used an arcane connection is formed from the activator to the item for one week per magnitude of the power.


Wizard’s Auger, with an example of spell penetration

Sharing several similar effects demonstrating how Muto Vim might raise the penetration score of another spell. The most likely use is a caster to alter their own spells, as demonstrated in a similar enchanted effect in a magical axe in Magi of Hermes, p.51, which uses Range: Touch. To cast upon another Magi’s spells cooperatively R: Voice is required.

These spells demonstrate an interesting potential for Magi with high scores in Muto Vim; they may be able to spontaneously alter another lower level spell for which they have poor art scores to increase its penetration.

Example scenario – the junior Magus Argento needs to cast a sleep spell on a troublesome faerie soldier.

Argento has very strong Muto and Vim arts, and while she has learnt “The Call to Slumber” (ReMe10, Ars p.151) and cast cast it easily under normal circumstances against foes without magical resistance, she believes she will not have a high enough casting total or penetration to put the faerie to sleep due to her low Rego and Mentem arts.

Argento stats: Int 2, Stm 2, Muto 12, Rego 6, Mentem 4, Vim 11, Penetration 0, which means The Call to Slumber (CtS) has a CT of 10+roll, and a spont spell has a CT of 22+ before dividing.

Fearie Soldier has a Might score of 10. So Argento needs an effective CT+Pen of 21+ to put the fae to sleep.

Argento might try to roll 12+ roll vs the Fae’s Might of 10, however unless Argento is lucky and gets 9 or over on her roll, she will not succeed. This is because the Fae’s might will require a penetration result of 11 or higher more than the spell’s level to be successful.

Argento needs to choose to either repeatedly cast Call to Slumber at the faerie and hope that she rolls 9 or higher on the dice roll, or she can opt to boost her penetration using the style of spell below, with the the knowledge that each casting will cost her a spontaneous fatigue level. Note that if Argento learns Wizard’s Auger or Wizard’s Awl (below) formulaically, she can boost many of her low level spells easily, giving her better penetration – if she had, the poor fay would be asleep in the first round. This does not add any more than +5 to +10 penetration to a spell, but that little extra is sometimes all that is needed.

Argento chooses to first cast a spontaneous version of Wizard’s Auger as a MuVi10 spell, for which she has a casting total of 25+ roll before halving the result by spending a fatigue level. Unless she botches she will succeed, and this raises the penetration of the next spell by +5.

She then casts her Call to Slumber as normal, and while she still has a CT of 12+, her final penetration for the spell is now CT+Pen of 17 + dice roll, making it far more likely that she could put the annoying fae to sleep. She only need a 4 or more on the d10 roll.

In this scenario yelling with powerful gestures also helps both styles of approach, it makes the casting without a MuVi spell far more likely, however it makes the solution with a MuVi spell almost a certainty (botches, twilight, etc).

Learned formulaically these spells add a lot of utility without requiring significant additional power or lab level. A Muto expert could also spont cast their own versions easily, and also might help their troupe if they cooperate with other Magi. Continue reading

How does MR and Penetration work in Ars Magica?

I swear on all things unholy that the descriptions in Ars Magica 5th edition on how Magic Resistance (MR) and Penetration work are confusing. As a roleplayer’s PSA here is my breakdown of how it works, with a worked example that explores some of the edge cases you’ll encounter.

(I’ve checked with the gurus in the Ars Magica official forums, so the worked example below should be accurate.)

So how does MR and Penetration work in Ars Magica?

The simple explanation is that the penetration total for a spell must be higher than the target’s magic resistance. If they have no MR, then the spell effects are resolved as normal. So the Penetration total must exceed the MR.

As a basic principal the more raw power the Magus has to cast the spell the better, however that power is used for the generation of the spell effect and also for determining if it can pierce the Magic Resistance of the target. Essentially the more power the Magus uses in generating the spell, the less power they have to defeat any MR they might encounter.

That might seem odd, but it makes sense when you consider that most mundane targets (most normal humans) have no magic resistance at all. So against those targets the caster can opt to use their best very powerful spell (such as an instant death spell) instead of a far weaker spell that might just hurt or paralyse the target. The lesser powered spell might harm a creature with MR, as more of the remaining potential energy is being used to penetrate the creature’s resistance.

However almost all of the supernatural creatures, Magi, and some holy men do have magic resistance from various sources, and their MR must be overcome before considering the effect the spell might have. Thus the Ars Magica rules were updated in 5th edition to demonstrate that MR is valuable and something that Magi must consider when fighting with magical enemies.

So the penetration is the remainder when spell’s power level is subtracted from the power the magus generates. This means that sometimes the penetration value (the remainder) is less the magic resistance of the target, and therefore the spell is repelled. Sometimes the remainder is negative, which means that while the spell was cast successfully, the spell could only affect creates that have no magic resistance at all. i.e. It would only affect mundanes.

Continue reading