Fast travelling to the Maw will have put you out at the exit to the Breach.
Cross the bridge here and go all the way to the South this time. As you reach the opposite side, to the left you will find an optional dungeon - Sentinel's Gaze. Ignore this for now and do a 180 to see a building opposite. Head inside the open door and fight the skeletons here. Continue down the stairs to the right and when you reach the balcony overlooking the gorge, look to the right for a Boatman's Coin .
Head back inside and from the entrance, look in the left hand corner to find a block we can wall run up to. Using the various handholds and blocks here, make your way up the wall here all the way to the top of the structure. Follow the passage around past the gates to the other side. Look in the open doorway here for a Soul Arbiter's Sacred Soul. Exit and climb some handholds just to the south of your current position. Up here, turn the green lantern statue 180 degrees and it will open up some gates containing chests that we saw earlier at the Breach, but were unable to access at the time. You can head back and grab these at your convenience.
Return to ground level and head over to the ominous looking door to the South east of your position. Make your way inside and run up and strike the crystal in the centre of the circular platform here to activate a lift that will cause you to descend into Phariseer's Tomb.