I'll take a stab at making a promo curser.
Here's
Heretic. Super swingy alt-vp that allows you to do an absurd thing like get all the curses and use them instead of money.
Card text is :
While this card is in play, Curses gain the type "Treasure" and have the ability +$2.
Choose one or both:
• Gain a Curse to your hand.
• Each other player gains a Curse.
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At the end of the game, if you have the most Curses, 2%
you'd clearly want enough of them to make them actually worth VP to offset the curses you take on.
Alternatively, you can just curse everyone else, and/or yourself!
Also ties into the promo's subtheme of "generally large/strange choices" (Governor, Envoy (for the player on yr left), Prince and Stash also exhibit a similar "large" decision space, Black Market exhibiting "strange" decision space).
Thematically, its named "Heretic" because it involves having a large pile of junk, and "religious"-themed cards are generally de-junking trash cards.
edit: fixed image link, added thematic rationale