If you have AOE attacks, use them to aid Kormac a bit. You should focus on one pillar at a time, and let the Templar deal with the spawns. Destroy the activated pillars, and the enemies. The ghost of Leoric will activate some pillars that summon skeletons. Keep going, there is a room with four pillars. Interact with it for a small story scene, showing the ghost of Lachdanan executing Leoric. Your new task is to find the Crypt of the Skeleton King. Eventually you reach the entrance to the Royal Crypts. Break any wooden doors you see, because many of them lead to rooms with chests and treasure. You might also encounter a harvester elite boss, such as Drekavac Filthpit. You should find a Scribe's Lectern, with a green story item: Lachdanan's Scroll Part 2 on it, which will be added to your journal. Open your map once in a while, to get some orientation. If you kill an enemy with one of those, you will get the achievement: Light Entertainment Kill a monster with a Chandelier The fourth level of the Cathedral is a pretty big one, so you will have a lot to explore before finally reaching your exit.

There are lots of crumbling walls in this level, so it is a good spot to get the achievement: Bringing Down the House Kill 10 monsters with the environment There are also Chandeliers in this level, which you can cause to drop by cutting the rope. If you die, you revive at your last checkpoint. They will be joined by Harvesters and Skeletal Shieldbearers.

You will come across some Tomb Guardians performing a ritual, break their ritual. There are also Skeletal Archers in this level, that attack you from range, and the usual Skeletons, Tomb Guardians, Fiends, and other undead. Take it, and descend through some spiral quest to fight some Harvesters (Knockback). You also get the following achievement for having the templar, Kormac, as your follower: A Boon Companion Acquire the Templar as a follower The exit to the Cathedral Level 4 should be nearby. In the battle against the Skeleton King, this skill we be useful.

As previously mentioned, it is important to left click on your follower's icon, and assign him the HEAL skill, a level 5 skill. Your current objective in the quest 'Reign of the Black King' is to search for the Royal Crypts.

Diablo 3 map cathedral level 4