Maghda

Maghda was a witch, a minion of Belial, and the leader of the Coven.

Youth
In her youth, Maghda was a member of a group of witches that operated in Westmarch. It was here that she met Adria. Years later, both witches joined the Coven and took control of the group after killing its leaders. Adria later departed the Coven after a schism with her partner, around the time of the Darkening of Tristram.

During the Game
The player first meets Magdha during the Sword of the Stranger quest of Act I, where it is revealed that she is after the three pieces of the sword that fell into Sanctuary along with the mysterious Stranger.

After failing to kill the player in the Drowned Temple, she turns her wrath toward the fishing village of Wortham, where the final sword piece is, and burns the place to the ground, killing most of its inhabitants. She captures the sword piece there, then captures Leah, Deckard Cain and the Stranger, who have the other two pieces. Maghda's torture of Deckard Cain proves fatal to him, but when Leah unleashes her power for the first time, Maghda settles for capturing the Stranger if she cannot have the sword. The player pursues her through Leoric's manor and Leoric's old torture chambers before rescuing the Stranger, who reveals himself to be Tyrael once the sword is returned to him.

The hunt for Maghda takes up the first part of Act II, where the player fights the Coven in the deserts of Kehjistan, and tracks her to the Khasim Outpost, where she is planning to sacrifice Captain Davyd and other Iron Wolves to Belial. The player points out to Maghda that Belial used her as bait to lure him or her away from Caldeum, to which she doesn't react well. The chase ends in Alcarnus, where she and her Coven have been torturing and massacring the villagers, and the player finally confronts her in the Lair of the Witch.

In-game
Maghda appears as a boss in Act II of Diablo III.

Moves
In addition, her Uber appearance has the following actions: As noted above, Maghda's strongest attack is her powerful summons. Maghda will not drop the shield until all of her minions are dead.
 * Spit: Maghda will spit flies at a close hero, dealing low damage.
 * Swarm of Flies: Maghda summons a swarm of flies, who then make progress towards a distant hero. This causes low damage upon contact.
 * Summoning: As the fight drags on, Maghda will summon varients of the cultists fought throughout Act I-II, as well as the Dark Berserkers. All of these beings possess the same actions as the normal variants, but heroes should be forewarned that the first wave of Dark Berserkers summoned will have Frozen, and the second wave of Dark Berserkers will be Molten.
 * Arcane Enchanted: This allows Maghda to periodically throw out an Arcane Sentry. This sentry will appear as a purple orb with a line being emitted. This sentry will do high damage, and ticks very fast.
 * Shielding: This works just like her normal appearance prior to the pre-expansion patch, only the creatures summoned are named Thralls of the Witch instead.

Personality and Traits
Maghda is a cruel and pitiless witch who will shirk from no atrocity to get what she wants, but she is also a coward who does not engage in direct combat with her enemies if she can help it unless she knows that she can destroy them personally, and frequently appears in spectral form in order to taunt the player. Based on dialogue during the final battle against her, it appears that she is relatively gullible, as she actually believed that Belial (Lord of Lies) would never betray her, which he did by leaving her to fend for herself against the nephalem hero.

Trivia

 * Maghda is voiced by Susan Blakslee, who's most notable for being the primary current voice of the Disney character Maleficent, to whom Maghda bears some resemblance.
 * Maghda is one of the six Boss Monsters of Diablo III to have an Uber appearance. Her Uber version sports little changes in strategy compared to when players fight Maghda in Act II, but she is also Arcane Enchanted. She fights alongside the Uber version of King Leoric, and she can drop the Writhing Spine upon defeat.