Target-Based Magical Foci Applicability

Games Discussion Ars Magica
1

Couldn’t think of a more synthesized title, but my question is this: given certain magical foci being somewhat based on the target of the spell; how do you deal with calculating casting totals? Is a separate spell required to take advantage of the focus, or can you have “multiple base casting totals” for the same spell?

Quick example: A magus with a minor magical focus in “wolves” has a PeAn spell that does a certain wound level. Do they have “two casting totals” - one as normal when casting this spell on say, a dog or sheep, and a separate (higher) casting total when using this spell on a wolf, or do they need to invent a separate wolf-attacking spell to take advantage of their focus?

I’ve been pondering this with regards to spells like Sulemain’s Wrath on the Oath-Forsaken Djinn for example, which actually works as a generalized Magic-realm might-stripper from my reading, though it appears “aimed” initially at dealing with spiritual entities, it could be used to lower the Might of say, a beast of virtue - though obviously the Sahir’s magical focus in dealing with elemental spirits shouldn’t apply in such a case.

Thoughts? Is there a guideline I’ve missed somewhere?

2

If it's a spell with a wider target base than your focus, you don't get the focus bonus when inventing it, or on casting it on something outside your focus, but you do if casting it on something within your focus.

Alternatively, you can create a narrower version of the spell which only works on things within your area of focus, and get the focus bonus to the lab total. This is one potential explanation for spells which are narrower than they need to be.