Diablo 3 City of Blood

The barricade the Cultists set up on the Road to Alcarnus has forced you to take a detour through the Khasim Outpost and has given Maghda more time to fortify her position. You should proceed without delay.

Captain Davyd unlocked a gate leading to another section of the Stringing Winds that is separated from the previous area by a large ravine. Gradually make your way south while crisscrossing the Stringing Winds desert to accumulate as much treasure and experience as you can from monsters in the area. Make your way south-east towards the Road to Alcarnus.
Shatterbone is a very big Berserker-type creature with a powerful mace that it can swing across or down at you. He also has a lot more health than typical Dark Berserkers because he has the Extra Health trait. His horizontal mace swings land quiet quickly, but you can weather those. What you must really avoid, however, are his vertical mace swings, which are Berserker Power Hits. These inflict 3x the normal amount of damage, but they also cause his mace to become stuck in the ground for a brief moment when he swings and misses his target, which leaves him open to a counter attack for a few seconds. Because of this, your strategy should be to watch carefully for when he raises his mace far behind his head to perform his vertical swing, then dart to either side to avoid the descending strike and, while he’s pulling his mace out of the ground, circle around him and strike Shatterbone from behind.
There’s a waypoint nearby in case you want to return to Hidden Camp to stock up or do anything else. Take the time to explore the western region of this area before heading east. The entrance to Alcarnus is only steps away, right through the gate, but there are enemies to overcome first. Lure all the surrounding enemies away from the creature called Shatterbone and kill them first so that you’ll have health globes available in case you have need them when you fight Shatterbone.

Proceed across the bridge into Alcarnus. Maghda is not far, but her minions have this town very well fortified. Your strategy should be divide and conquer. Advance through the town slowly and draw enemies away from their comrades and pick them off one at a time or in small groups. Fight your way eastward past the cellars along the southern part of the town. You can use your surroundings to your advantage by keeping the buildings between yourself and those enemies that case magic at you.

Maghda won’t be fleeing this time; she’s finally going to stand and fight. Don’t think she’ll be doing it alone, though. At the start of the fight she will summon five Dark Cultists to aid her. Eliminate these minions as quickly as possible and then target Maghda. For the rest of the fight she will summon Berserker pets in groups of three. Maghda’s gauntlets are inset with the Teeth of Diablo, which allow her to buff the minions she summons, making them tougher to kill than standard Berserkers. Attack her minions only when necessary to defend yourself; you need to keep dealing as much damage to Maghda as possible.

Continue to move eastward, then go up the stairs to the north where several groups of cultists are standing in ritualistic circles. Try to kill the Corrupt Vessels before they can be transformed into Tormented Thralls.

Maghda is located in the north-east corner of Alcarnus. Before going there to face her, you might want to use the Town Portal to return to the Hidden Camp and Caldeum Bazaar to stock up on supplies and see to the condition of your equipment. This will make the coming battle with Maghda go much smoother.
Maghda has numerous attacks and abilities, but does not possess any elemental resistances or special traits. Many of her attacks utilize her control over moths and other insects. If Maghda is attacked at close range, she will open her mouth and spew forth a swarm of tiny moths that inflict periodic damage for as long as you remain engulfed in the swarm. She’ll also throw an energized cloud of moths at those who attack her from distance with ranged attacks and powers. This attack will not harm her summoned Berserker pets.

Maghda will teleport all about the battlefield throughout the fight, particularly when she receives heavy damage. She’ll vanish for several seconds while teleporting; use this time to attack her minions and to pick up any health globes lying about.

The hardest thing about this battle comes when Maghda raises her Forcefield. When this happens, she is completely protected against all attacks. In order to make her lower her Forcefield, you have to kill all her summoned minions currently on the battlefield. When they’re all dead and she lowers her Forefield to make her next move, hit her with your most potent attacks and abilities.

When Maghda lies dead, use the Town Portal to return to the Hidden Camp where Tyrael is waiting for you. He tells you that while you were off hunting Maghda, Belial abducted Leah. Without Leah, only Asheara can help you enter the city. You’ll need to go and talk to her at once.