PeCo(CrIm) 30 - Voice | Sun | Ind | - False Immolation
While you concentrate, the victim keeps on burning, the skin peels away due to the flames, blood boiling and pain, so much pain. Stop concentrating and the flames disappear but the burns remain along with the pain they should confer but the caster can alleviate the pain if he so wishes only to bring it back along the with the fire whenever he whims it.
Bystanders see the horror also. This is truly a horrific sight! when the effect ends, only the mental scars will remain.
(Voice +2 | Sun +2 | Ind +0 | Base 4, +1 Imaginem effect, +1 CrCo effect)
Concentration spells usually require one of two things, either Concentration duration or a Rego requisite. Other things seem not to have the spell vary but make a target malleable in some way, allowing vocal commands and the like.
If you've actually done the damage, then actually healing the damage requires a ritual and Vis. It doesn't seem that's what you want.
That's not how Perdo works. If Perdo does damage that damage cannot be restored until the duration ends. A perdo spell, unless you have the Harmless Magic flaw can't create damage that expires when the effect ends. You might, might be able to get away with doing something via Muto... But I'm not aware of any guidelines that do this.
For the 1st point, it's an interesting interpretation of the concentration guideline. So ReCo effects that move things around with a duration greater than concentration would have to pay an extra magnitude on top of everything else in order to allow to change the direction or speed. Interesting.
For the 2nd point, the damage is "virtual". I'm using the base 4 guideline of pain to simulate the damage. The CrCo effect would just calm the pain ... offer somekind of bliss in comparison to the previously felt pain. I guess it could be CrMe or MuMe also.
As callen said, 'concentration' spells (those that grant the caster ongoing control) require either Concentration duration or a Rego requisite. The Rego requisite is unnecessary for an actual Rego spell, so a Sun duration ReCo spell would be assumed to grant the caster ongoing control for Sun duration.
That sounds to go against general guidelines. Even if it is a Rego effect, allowing the spell to have ongoing control seems like an additional "power/complexity" hence +1 magnitude or do you reduce the spell by one if the Rego spell does not allow it?
I quickly browsed the core book to find a counter and located Phantasmal Animal p.144. Seems it costs two magnitude surplus for the effect. By reading the CrIm guidelines, the pain/no pain effect could warrant one "complexity" magnitude.
CrIm(Co) could be used to create false pain, I believe, by creating an actual illusion of pain. I believe there's something about that in the HoH:S Jerbiton chapter (serf's parma!).
I always thought using PeCo to create pain was a method that would leave marks: actually inflicting damage, just not enough to warrant a wound. A pure illusion of pain might be more what you're after, and may let you drop a requisite in the process.
I just re-read that section and they define pain as a secondary sense but not really? and have it managed by Memtem. So we might have to add a memtem requesite and switch the CrCo extra magnetude under PeMe to have the pain on/off during the duration of the spell.
I'd go with CrIm(Me/Co?) in that case. Rego requisite for the added control optional, based on the preference of the troupe for how variable-control spells are handled.
I personally wouldn't require a Perdo component since you're not actually destroying anything, and if Mentem is the requisite for illusionary pain then Corpus isn't needed either. Assuming you're not planning on doing any real damage with the spell.
You could alternately just have the spell with a fixed duration (lets say Sun) and switch it on and off using Suppressing the Wizard's Handiwork.