Hub 4: Desolate Garden

Desolate Garden is a secret level in the fourth hub of Hexen. It is only accessible by crossing a linedef in the map Bright Crucible in the first hub and pressing a switch in the map Sacred Grove in the second hub, or by using the "casper" cheat code.

It is the 25th map in Hexen, but is named MAP26 in the WAD file.

Walkthrough
In this map, you can collect all three pieces of your fourth weapon, if you haven't done so otherwise.

Look for the three superweapon pieces here:
 * Behind the exit portal, where you overlook the main courtyard
 * In the eastern slime trap room.
 * After triggering and disarming the slime trap (by pressing the eastern-most switch), return to see the final piece of the weapon.

You will start in an open courtyard, with a 3-by-3 arrangement of switches that will rise and lower. There are also enemies attacking from the windows in the eastern and western walls.

You will need to pull switches to unlock parts of the level. When you pull a switch, one random monster will be summoned, except for the central switch which will summon a group of Dark Bishops.

After pulling four switches, you should have both the northwest and southwest elevators active. If you cross the upper threshold of both elevators, there is a delay of 14 seconds before a section of the western corridor opens, giving access to a Krater of Might.

After pulling six switches, you can access the stairs leading to the east of the map. There is a room containing slime, and entering it activates a trap. There is a short delay before the trap activates, and leaving the room makes the contents inaccessible. The trap seals you in the room, requiring you to activate a switch in the eastern end. When the switch is activated, the room will drain and you will see a superweapon piece just outside (along with a Green Chaos Serpent).

When you pull nine switches, the exit is available between the two stairs. Remember to circle around the exit portal to collect the last superweapon piece.

The exit returns you to the Forsaken Outpost.

Mage Class
In addition, for every player class on every skill level there are 8 random monsters which are spawned when outer switches are pulled. They can be of the following kinds: Ettin, Afrit, Green Chaos Serpent, Centaur and Slaughtaur.