Diablo III

Maghda is a fairly tough boss who primarily uses ranged attacks. She also uses a shield technique that makes her invincible for a short time. To break the shield you must defeat the minions she summons which can be a good thing as you might need some health orbs out of them.

Starting out she is reluctant to use her shield so pile on the damage quickly to put a dent in her HP bar. Once she starts losing health she will begin cycling out minions and her shield. This is the "Cat and mouse" portion where it should be easy to out pace her by using her minions as a source of HP. Stun works particularly good on her to prolong the onslaught when her defenses are down.

Like most story bosses when she is close to death she becomes much more aggressive and opts for an all out assault. This is your chance to duck and dodge her attacks and land the death blow.