Etumer is the trigger NPC for the Mujaki the Devourer fight.
He is an Erudite with a shovel, who's wandering around the Gargoyle city, moving along all the tombstones and graves there. In order to activate the Mujaki event, you need to hail him.
You say, 'Hail, Etumer'
Etumer looks at you with wide, wild eyes. 'Who.. what.. who are you? If you are a sending from my brother, you will not take me so easily!'
You say, 'What brother?'
Etumer says 'Mujaki! Haha! He.. He captured me and.. imprisoned me here as punishment for some supposed transgressions against him. Mujaki always was jealous of my own prowess and resentful of our fathers favor toward me. He has only further proven his weakness through trapping me with power granted to him by Terris Thule. Hmm, perhaps..'
You say, 'Perhaps what?'
Etumer says 'Perhaps you could find some way to overwhelm Mujaki? I might be able to work an enchantment to transport you closer to my brother. I only feel I have the power to send twenty four of you, when you have formed rank please have the leaders of your groups let me know when you are ready.'
You say, 'I am ready'
At this point, everyone in the immediate vicinity of Etumer gets teleported into the quest area. It's a large square outside area, with a wall splitting it in two, right through the middle. You can pass around this wall on either side, close to the outside wall. Mujaki is on a platform on the other side, untargetable. Three large green obelisks are at three different directions from the platform. The mobs will spawn there and move up to the platform from there. The waves come at 2 minute intervals. If a servant reaches the platform, he will mount up and become untargetable. Once 36 servants have been either killed or reached the platform, Mujaki will become targetable as will any of the mobs that reached the platform.
After starting the Mujaki event, Etumer won't port or start another event right away and says the following:
Etumer says, 'I... I don't think I can muster the force to work this teleportation. Allow me to rest and return to me later, perhaps I can work it then.'