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.
The Iron-Bound Tome 