Using that term losely, but here's Reylai and her 'cousin' Raxfel. Whereas Wulfenmother is the mother of all werewolves, her sister Jezelda is the mother of the plague, taking the werewolf gift and twisting it.

Wulfenmother has Reylai...and Jezelda has Raxfel, who we've properly encountered in campaign all of once and it was a disaster. We won, with Reylai landing a heavy enough hit that he was plane shifted away due to being part abyssal (for the unitiated, creatures with ties to other planes can't easily die outside of their plane), but had the fight lasted a round or two more it was likely someone would have dropped.

I know next to nothing about him still, but I can't say I'm eager to run into him again.