User blog comment:Hyperborean/"The House of Hades" – official expectations blog/@comment-50.53.164.184-20130328214721/@comment-3146930-20130328215707

Well Tartarus is a place for monsters to reform until they become strong enough to return to the mortal world. But it is also where they are at their strongest. If a monster is killed there, it could instantly reform as it is already in their respawn point.