Some of the curse descriptions sound like they come from an incredibly spiteful demon, while others sound like they were cast by a mildly irritated wizard.
"your nails grow twice the average speed, they bleed when cut."
Innocuous enough to not curse one's ancestors, but annoying enough to leave nails unclipped for quite a while. lol
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Certainly an interesting character creator, and I didn't know much about Tieflings before starting to read this.
My guess is that more often or not people making a tiefling for the most part just wanted some cool undercover vaguely cursed character to stroll around with with the rest of the party.
Playing with someone that is a walking omen factory is like turning on hard mode before even starting the game. :P
Good job putting this all together!