Are devils worth 7 blood each?

[Alneyan]

If you are found by an Astral mage, can you still attempt to kill one of the commanders, or is the attempt aborted?

Even if you have to avoid Astral mages to ensure a kill, this spell should be useful if you have cheap Astral mages and/or ways of curing the likely feeblemindedness. Even an Astral mage 1 should be able to cast this spell with the Astral boosting equipment, although it would be fairly expensive to forge all of them. But since the mage isn't killed, even after a failure, I guess it may pay out after some successful castings.