Shattered Kingdoms

If you want to get someone in a cabal HQ, get three GMs together, with a good mix of classes, and own the outer guardian's face. It isn't hard. The guards that spawn are sometimes harder than the outer guardian, depending on what class set you're working with in your group, but as long as you have someone with group-affect spells (priest, warlock, sorc, necro, shaman) even those will drop relatively easily.