The Morden Chief - Act 3 Story Quest
The Morden Chief is the 2nd Story Quest of Act 3 and begins immediately after you complete Restore Kalrathia's Water. For this quest you will have to exit Kalrathia out of the eastern gate and travel through the Eastern Plain of Tears. You'll pass a couple different Side Quests along the way, all of which are listed below.
Side Quests In Area:
If you're the sort of person who likes to explore every nook and crany you'll also come across an area called Large Abandoned Shelter which you may swear is involved in a Side Quest but it is not. It's just a large puzzle area and the only reward is a Greater Chant of Ranger Power Lectern.
The City of Darthrul will be one of the more unique areas that you have visited in the game thus far. When you first arrive you'll only have access to one area of the city and in order to progress you'll need to defeat elite Morden throughout the city. In each area of Darthrul you'll always find an elite Morden which will drop a key to the next area of Darthrul.
With this knowledge in mind, work through each District 1 by 1 until you've cleared them all. You'll find a total of 5 districts in this city;
District of the Sword
District of the Crossbow
District of the Lance
District of the Chief
District of the Shield
You only need to visit Sword, Crossbow and Lance to get the District of the Chief key which will give you access to the Morden Chief. However if you go down the elevator nearby where you acquire the District of the Chief Key you'll find an elite Morden who will drop the District of the Shield Key that you need to access the final part of the city. This will lead you to a Side Quest, The Morden Riders as well as a bunch of other enemies.
At the northern most point in the City of Darthrul you'll find the Morden-Viir Chief (pictured above) whom you'll be able to speak with before you fight. No matter what dialogue options you choose you'll still end up fighting him. Once you've defeated him and his cronies port back to Kalrathia and speak with Lord Kalrathia.
This quest will be completed when you speak with Lord Kalrathia and the next one, The Kalrathian Rebellion, will begin.