None of the comments here are clear at all on where to find Araxxas. I finally found him after scouting out the entire area. There are 2 ways to get to him.
If you're already in the compound: Standing at exactly 43.86, 50.34 there is a set of stairs you can go up. Take a left at the first landing. Keep going straight when you reach the top and you'll see Araxxas.
If you went outside: Standing outside and facing the Ravencrest Mausoleum where you get the quest from Jarod, to your left is a short ramp then to the immediate right is a set of stairs going up. Take both. You're now on a ledge that goes around a tower. Follow it around (short trip) and take your first right across the bridge to the rampart. There are a couple guards that you'll need to take out and watch for the ghost windgryph riders. At the end of the bridge, turn left and follow the curve of the rampart. You can't miss Araxxas when you get to him.
To turn the quest in, go thru the door behind him and down the spiral stairs.