Something I have always wondered about is why some virtues and flaws are in multiple categories. Usually it does not make that big a difference to me, but when looking at the Tainted items in RoP:TI, it has me arching eyebrows.
For example: Amorphous (Major or Minor, Supernatural, Tainted), Aptitude for Sin (Minor, General, Tainted), Convoluted Mind (Minor, General, Tainted)
Same thing with the flaws.
Does this mean that the virtue can be taken as either tainted or as general/supernatural? Or would it always just be tainted? What is the purpose of having multiple categories listed?
See RoP:TI p.82 Tainted Virtues and Flaws: a Tainted Virtue/Flaw is always Tainted, even if it is also listed as Supernatural and Major or such. Read also there "..., and characters who are not tainted may take them during character creation or receive them in response to Infernal Warping. However, a character should not begin with more than half of his starting Virtues or Flaws Tainted."
So having a Tainted Virtue or Flaw does not automatically make a character a Tainted Character (RoP:TI p.96ff) - but it certainly means, that this character had run-ins with demons that left their mark on him.
For example, Amorphous is a minor supernatural virtue, who also happens to be a tainted virtue (Which, IIRC, means that Sense Holiness & Unholiness perceive it as Infernal)
Note that, although not listed and often forgotten (By me included), this type of thing also apply to supernatural virtue, in that they should have a realm of affiliation, meaning that one character could have Divine-aligned second sight and another an Infernal-based Shapeshift virtue.
This is important, due to realm interaction: Your Faerie-based Enchanting music may not work very well in an infernal regio.
(However, due to the predominance of the divine, forgetting this doesn't bug me much, since it avoid characters being all tempted to have Divine supernatural virtues)
Thank you, it now makes a lot more sense. So during character generation, it would make sense to keep to the tainted classification instead of (for example) adding a tainted item as a supernatural and then forgetting/players forgetting it is tainted...?
Tainted is an extra classification. If it's purely Supernatural from the Infernal, then it's just Infernal, not Tainted. Tainted is for something from the non-Infernal with a touch of Infernal upon it. So all the Tainted stuff should remain Tainted, but it also qualifies as whatever it is normally. That's why you see the double classification. Anything Tainted should always be Tainted as well as having some other classification.
Things with Tainted are Magic or Faerie in nature (so affected by Aura as that type), but are perceived by the Divine as Infernal. So things like Sense Holiness/Unholiness would detect them as Infernal (or at least partially Infernal).