This is the the final quest.
Once you beat the Arena, you need to meet Ashur in Haven. So...
1. Get your gear from the footlocker by Faydra.
2. You need to leave the Arena. Two options: head through the Steelyard. Once you pass the guard, enter the door up the small ramp. Or, you go around to the other side of the Mill and head through a gate to Uptown.
3. You'll walk through Uptown for a bit. Up and over a building and eventually out of the city gates. There is a suspended walkway and a nice looking statue for you to walk underneath. Enter Haven!
4. Find "The Cure". See below...
After talking to Ashur, you have two choices:
1. Take the baby, she is "The Cure"!! She's located in the room with Sandra. This sides you with the slaves. Then you need to get the baby to Weurher in his secret hiding spot, then turn out the lights on up town and escape.
2. Or leave the building. This sides you with Ashur .