While I appreciate you trying to put mechanical values to fluff things (purely to make the auras more flavourful), I'll just write in the class description that they don't affect mechanics in any way.
I recommend explaining that it is all in people's heads, rather than leaving the reason WHY it doesn't effect mechanics hanging.
Originally Posted by Sir_Chivalry
I don't think anything stronger than an Erinyes would take much an interest in mortals becoming blackguards.
Well, if the Blackgaurd is coming to the class late (which, for fluff reasons, a lot of them would) then as long as the CR and other measures of the importance of the mortal are high enough, I don't see why it wouldn't. Or are you just saying that the fluff for every existent devil already that is higher CR than an Erinyes doesn't indicate much of a "claws on" approach to the mortal world except in cases where their claws literally become involved? Of course, as long as the fiend remains a trivial challenge to the black-guard, it doesn't matter how high their respective levels get.
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