I missed this until late last night:
This is the newest addition to the DF line. It adds templates for Demon-slayers, Mage-slayers, and Undead-slayers to DF.
I'm intrigued although unlikely to just add them to Felltower. It's a very specific type of campaign, really, and I'm wary of disrupting its, ahem, "balance." But I will get this and read this because Sean Punch.