By the time you face Azmodan, you are likely used to bosses coming in two varieties; massive melee beasts that dish out heavy hits but otherwise aren’t troubling, and tricky pestering bosses that aren’t terribly damaging as long as you pay attention to the various threats they generate.
Azmodan is a rather alarming change from this- his combination of melee and ranged powers lets him dish out staggering amounts of damage if you aren’t careful, combining both the difficulty of monitoring your battlefield and monitoring your health.
Azmodan packs a staggering five special attacks, nearly twice the number that you’ve seen before, in addition to his hefty melee swings.
The Lord of Sin’s first and most frequently used special attack is a slow, burning magma-ball that he launches. Despite the thing’s low speed, it moves to follow its selected target, so while you don’t need to worry too much about the thing catching up to you, that only applies as long as you remember to try to evade it.
The second power that Azmodan is likely to use on you creates a large reddish ring on the ground. A few moments after the ring appears and for a bit of a while afterwards, exploding corpses rain down on the affected area. While the area is easy to spot and make your way out of, since the corpses do not cause knockback or stagger, the damage they can deal out is fairly strong and the area of effect of this corpse rain is distressingly large.
Third of all, Azmodan packs a beam attack similar to the Wizard’s Disintegrate spell. It’s not quite as powerful, but he can hold onto it for a good while, and it’s got fairly nice range. Backing off or running in circles around him will usually keep you from getting blasted too much, but you’ll want to have ahold of some form of healing if you either get trapped in a ‘corner’ or otherwise prevented from avoiding it.
Fourth, Azmodan echoes his Siegebreaker Beast- if you are in melee with him, he may periodically pick you up and bellow in your face. Unlike the siegebreaker, Azmodan’s mouth is full of blistering heat, and the damage he deals by howling at you is even more excessive. This is his second-most-dangerous offense, and a very good reason for anyone not a Monk or Barbarian to stay away from his reach. Thankfully, even on them he doesn’t use this attack very often at all.
Finally, the most devastating of Azmodan’s attacks is one that he thankfully triggers only periodically- but he can use any and all of his other powers while it is going off. This ability of his causes pools of blackness to appear and expand all over the battlefield, one by one. Each of these pools covers more than half the area you can view in a single screen, and over the course of ten to twenty seconds, he can reduce the safe area in his entire arena to a few misshapen spots of clear ground. Thankfully, they pass after another ten to twenty seconds once all of them have spawned, but in the meantime- stay out of the black stuff. These pools are pure poison, and they will eat your life away faster than anything else Azmodan does. This is especially dangerous because the poison pools overlap, but since all of them are pitch-black, you can’t actually see clearly how many you’re standing in at any given moment.
Azmodan is a boss you have to be willing to take your time with- while his health is low enough that you can really pump a lot of damage into him, the Lord of Sin’s pools of poison absolutely must be evaded, and the corpse rain and magma ball will make fairly short work of you as well with repeated hits. Be ready to escape these nasty areas of effect, even if it means not hitting the Demon Lord for a while.
If you can manage to keep your head on and stay out of the nastiness he spreads on the floor, fighting Azmodan becomes relatively easy, if dangerous- just misplacing your feet enough to stand in black poison for a few seconds can spell doom for your challenge to his supremacy. Stay alert, stay on your toes, and keep dishing out the hits when you get the opportunity.