Hi! I've been away from the forums for a while, and tend to only post in brief flurries of three or four posts before reverting to lurking, but in effort to actually contribute something...
Here's a couple virtues I made for an Ex Misc tradition in my game. I've only recently become confident enough to try making custom abilities and such for the game, partly inspired by the Societates book, so I'm not sure how well this is balanced. I'd value any opinions the rest of you might have.
As a note, this tradition has no basis whatsoever in history, as far as I know. It's for a fairly high-fantasy game. I'm just asking about the game balance of the virtues, as they could be re-flavored easily enough anyway.
EX MISC TRADITION:
Major Non-Hermetic Virtue: Touch of Decay
Minor Hermetic Virtue: Dissolution Magic
Major Hermetic Flaw: Deficient Technique (Creo)
TOUCH OF DECAY (Major Supernatural Virtue)
At a cost of one fatigue level per use, this supernatural ability can be used to mimic any hermetic Perdo effect that causes physical damage or destruction of matter at touch range and momentary duration. The roll for casting total is (Stamina + Touch of Decay + 1d10), and the effect does not require any vocalizations or any gestures other than lightly touching the target. This ability can be associated with any Realm, though generally not Divine.
This is an accelerated ability, meaning that it gains levels at the same rate as Hermetic Arts.
DISSOLUTION MAGIC (Minor Hermetic Virtue)
This virtue allows you to add your Touch of Decay score to your casting score for any spontaneous Perdo spell you cast that causes damage or destruction of matter. It doesn't help with imaginem invisibility, ignem cold, or vim demon-destroying, for example, but can cause corpus wounds, destroy terram buildings, etc.