This is a level for Heretic. A group of Disciples of D'sparil are holding a ceremony to resurrect their fallen leader. In order to perform this ceremony they have taken control of a sacred elven church and killed its inhabitants. You must find the key, unlock its doors and put an end to their foul ceremonies. Of course, their monstrous minions are not going to let you just walk up and take the key, so you will have to deal with them first.