This quest is very easy compared with the loot it gives, if your not a druid, it might be a good idea to get a druid to clean to quest for you with Eternal Winter spell, since behemoths are weak against ice.
Before being able to go in the quest room, you need to pull a switch guarded by a dragon lord, first, go to cyclopolis.
Follow the next maps to the switch and the dragon lord, you will encounter each type of cyclops, dwarf soldiers, scorpions, fire elementals here:
Here you find the level 30 door, behind it are some fire elementals, down the stairs are 3 dragons and some more fire elementals:
Go down the stairs at the dragon floor(only 1 way possible so no map needed.)
Now follow the next maps to the dragon lord:
Up these stairs is the dragon lord, kill it, and west in the room you will find the switch under a fire field, it's the north one of the 2 most west fire fields. Use the destroy field rune on this field. Pull the switch(now the stones to the entrance will dissapear) and follow these maps to the quest room:
Use levitate spell here, you will end up on a small platform with 2 cyclops on it, kill them, go down the stairs(watch out, there might be several behemoths here!) Kill them or run to the north, go up the stairs, here is the lvl 80 door, behind it are stairs, up these stairs is a big room with 4 Behemoths, 3 Cyclops Smith and 2 Dragons. Kill them, the loot can be found north in the room. It's adviced to use a dwarven ring here, since the Cyclops Smith can make you drunk and you can't go down again in case of emergency.
Enjoy your loot!
Video of the quest
Here you can see Silent Defender soloing the quest. It shows a good way of how NOT to do the quest!