After an excellent discussion over here: Detecting spirits without intellego - #31 by Erik_Tyrrell
This is the revised spell
Illumination of the Immaterial Form [magic]
MuIg(Vi) 25
R:Touch, Dur: Sun, T: Ind.
This spell targets the light produced by a single fire. This targeted light reflect off of and fail to pass through immaterial spirits possessing magic might. Observers can see bright spots at a spirit's location from the reflected glow of the targeted fire, providing that the spell penetrates the spirit's magic resistance. Immaterial magical spirits in the vicinity of the targeted which posses shapes also cast shadows whether or not the spell penetrates their magic resistance. Not all immaterial spirits have a shape to be illuminated and not all of those that do have a shape at all times Airy spirits typically do not but ghosts and those spirits encountered by the nightwaker tradition from Hedge Magic Revised Edition typically do. A similar spell could be created for each of the realms of power although it is unlikely that an infernal version would ever be of benefit to the caster.
(base 4, +1 touch, +2 sun, +2 magnitudes complexity, requisite is essential)
At this point Ranulf's MuIg(Vi) lab total is 101, which means he can invent both Illumination of the immaterial form [magic] and a second twenty-fifth level spell that uses the same lab total. So he'll do this one as well.
Demon Expunging Flame
MuIg(Vi) 25
R:Voice, D: Diam., T: Ind.
A fire targeted by Demon Expunging Flame will burn the immaterial forms of spirits with infernal might. Such a fire removes 5 might points from a spirit for every full health level done by the flames (immaterial spirits rarely have any way to soak damage but a fair number of have complete immunity to fire. Ranulf developed ths spell knowing full well that the law of the infernal greatly hindered his ability to target it effectively. The spell can target fires of sufficent heat to do up to +15 damage which would allow him to use it in conjunction with Pillum of fire and the patient spell or more frequently a wall of flame created by stockade of infernos.
(base 4, +2 voice, +1 diameter, +2 fires of up to +15 damage)
Thsi is just a bit less effective than demon's eternal oblivion and it's also so fitting for Ranulf's style, it expands the capabilities of school of the founder specialists and it synergyses with many of his other spells. I like it, but if see an issue with it please tell me. I'd rather be right than happy with something flawed.