The Temple of Xayepocax is a room deep down in the Edron Hero Cave. It houses a quest and many, many different creatures. This is a great place to try and kill your first Warlock. A good strategy would be to lead him through the entrance's narrow corridor and then trap him in a corner. After the lvl 70 Gate of Expertise in the south of the room, you will find a teleporter which will take you to the Demon Forge (you will need lvl 100 to be able to enter it though).