I don't have The Infernal (but am considering getting it), but I have been wondering if there are any infernally-related flaws in that book that have a detrimental effect on a magus' Gift and magic-using capability. I'd check the unified Virtues and Flaws list, but I can't seem to get Adobe Reader to work. Details, even fairly vague ones, would be much appreciated.
I don't have my books with me but at least there is corrupted arts and corrupted spells.
Corrupted Arts gives a bonus when used sinfully but a penalty otherwise.
Corrupted spells is the same thing for a number of spells but the spell is too warped by the infernal corruption.
On the Gift, there is the false gift. Your gift originate from infernal powers, if you become pious you can loose all your magical powers.
Hope this help
Also, corrupted powers arts and spells:
- grants you additionnal experience towards the Art of Spell mastery if you succeed because of the bonus
- gives you negative experience if you fail because of the penalty (which may cause you to forget a corrupted spell).
As per a character with the False Gift, he does not experience twilight but vituperation (accelerated aging).
There is also Vengeful Powers (a favorite of mine), which, applied to an Hermetic Virtue, ensures that every time you use it for non-sinful purposes, something bad happen. For exemple, you bless your covenant's cultures, but a peasant will die in an accident.