Go through the secret door in the south east corner of Athron's lair, cross the bridge over the lava, enter the portal, and you will be in a room with a portal. In this reply I will call it the portal room. Enter the portal and fight your way to the portal and enter it. Go back to the room with the portal and enter it again. You will now be in the rune and gate room. Number the runes from left to right 1,2,3 and 4. Step on them in this order: 1,2,3,4,1,2,3,1,2,1 and enter the portal behind the now open gates. Go back to the portal room and enter the portal. Walk up to the altar until the walls open up. Fight your way to the portal in the western room and enter it. Go back to the portal room and enter it. You will ne in front of athron. Speak to her until she tells you that Vyvnas-Bok is in Angierach. go into the portal and go to Erika.