"Oh, clever," Lenore observes, considering the implications of that. "If the minor arcana are used to boost spells, for various purposes, such as a spell to heal or to grow, then the corruption of such a spell, to drain and wither ... it would make sense that such a thing would be kept restricted. Not in a library where just anyone"--especially someone newly arrived and of uncertain loyalties--"could easily access it. If I were managing libraries of magic and lore, I would bury dark magics like that so deeply that even mages of many years study and known loyalties couldn't find it, and with humans of shorter lifespans, perhaps even the most influential mages would forget that such things ever existed." In any case, it makes sense that it wouldn't be mentioned in the book in her arms, and in the latter case even the Rhett siblings might not recognize the withering symbol. But there's no way to prove that theory, and if Lucifer's right, it could have been newly developed once again--or discovered for the first time.

"Could we ..." Lenore taps a finger against the spine of the book, thinking. "It can't be as simple as reversing it. Though if it's on shrines where they're being held, it might well be worth the effort. If there's a capable enough mage amongst the captives, if we could get them this symbol. It probably wouldn't reverse the effects, but I imagine that if I had a shrine with a certain sigil doing a certain thing and someone cast a sort of anti-spell upon it, well ... that would certainly throw a hell of a wrench in whatever the original spell was meant to do." Probably a good idea to stand as far away as possible while casting that anti-spell.