I am looking for spell guidelines for interacting with ghosts. In the rule book, there is some interesting stuff about summoning or coercing. But is there some Ars Magica books with more details ?
For instance, I am interested in other interactions as:
Seeing invisible Ghosts (InMe)
Understanding Ghosts (InMe)
Healing Ghost might (CrMe)
Allowing physical contact with incorporeal ghosts (????)
I was sure I'd seen this effect as InMe somewhere, but I can't find it right now.
Easiest solution is probably InVi - which allows you to see (detect) beings with a Might score.
See Societates p. 99, Reveal the Lurkng Watchers
Understanding in what way? If you simply mean "understand the language it speaks", InMe Thoughts Within Babble (ArM5, p. 149) works just fine. You might want a version with longer duration though
Oooh! Big one. No current guideline supports this - however the guideline does exist for healing Demons (Infernal Might), and you could probably simply adapt this from RoP: I. It should probably be a ritual though.
Easiest way would probably be MuMe(Fo), where you transform the ghost (or part of it) into somethng solid. I'd suggest you took a good look at HoH: TL, p. 140, except I rather disagree with how certain of those spells were designed
To damage a ghost with a weapon i suggest or a enchanted weapon with a MuTe(Me) base to work against inmaterial beings (Base the change a aspect of the matter, +¡more magntiudes dependening de material) or the same like spell. Maybe a perdo or Muto Mentem to make the being feel bad or simply PeVi o PeMe against Might Score.
I am not looking at a way to hit Ghosts with weapon, but rather allowing to touch an incorporeal ghost, for example to hold it still, or even to hug a desperate ghost. I'm trying to design a Grimoire for Donatores (see HH:Societas).
Following your idea, MuCo(Me) can be a nice way to achieve it. Thanks.
Yes, but I think using Mentem, should allow to spot minds, whatever the Realm behind the Ghost. A spell base allowing to spot all minds (even living), should have a base lower than InMe 4 "Sense the state of consciousness..." because it is less specific.
If we take a base of 3, a generic mind detection spell should be of level 20 (Pers, Conc+1, Vision+4). Does it make sense ?
I'd probably go for a higher base - maybe 5 - but that depends on what you can convince your troupe it should be
I can definently see advantages to it being base 3
I'd call this MuMe(Co) because you primarily affect a spiritual thing, but change it into a physical one (although this is of little difference with requisites regarding invention/casting, it's mostly about which Form the spell is listed under). Sadly this is as high as base 25 (make a mind solid, with req. for Form).
I know "mind" isn't "ghost", however the base 15 guideline is for making a mind or ghost visible (with an Im req.)
I guess an Cr(in)Me spell would allow you to hear and speak with a ghost otherwise unable to do this. That could come in handy.
[Edit] Oh and I think for seeing a ghost Base 3 would suffice. That's what my Tremere Necromancer uses.
Where does this guideline come from? Per RoP:M p. 111, In(Fo) base 3 will only reveal a magic spirit of Might 30 or higher, provided the spell penetrates. You'd need base 5 to see a magic spirit of any Might.