Banished the Wicked works on werewolfs but I think the need to be transformed while you kill them to get the benefit from Banished the Wicked. Fun fact how much ultimate you can get from one kill:
* Be a Nightblade with Soulharvest slotted: 7 ultimate
* Banished the wicked maxed out and killing someone that is a Werewolf (The one you kill needs to be transformed I think) or a vampire: 9 ultimate
* Combat Frenzy (PvP skilline) maxed out: 20 ultimate
* Total possible ultimate gain from a kill: 36 ultimate
Might have missed something but I think this I pretty much the maximum you can gain from one kill.