You can also just walk into the shrine and start fighting. You will be able to talk to him a little while later after the main mission is done at the temple of one around the circle walk inside the temple. If you release the Argonian, His name I can't recall. We suggest releasing him and playing the good guy. Whether you do or not, alarms go off and you'll have to fight your way out. The Mythic Dawn members ask you to prove your loyalty and kill the Argonian they want to sacrifice. The Mysterium Xarxes, which is still in the shrine, becomes your target. When he finishes, he teleports into the realm of Paradise and takes the Amulet of Kings with him.
Follow Harrow down the tunnel inot a large open cavern where a ceremony is taking place.
First, you must give him all of your possessions and put on the initiate's robe. Through the next door, Harrow talks to you and says you may join. He'll tell you to go inside as he assumes you're looking to join. There are two ways to go about completing this dungeon.