Effect: Deals 20d10 fire damage in a radius of 15 around the player.
So you could probably take out all the lost souls by hand, then open the demon door, rush past them, they'll chase you to the boss door, you open it, instakill all the demons and probably severely weaken the AoD.
Lesse...
Health: 250 + 10×difficulty2 = 260, 290, 340, 410, 500
Armor: 10
So, if you're lucky, you'll do 190 against the AoD. At worse, 10, unless I'm really bad at dice notation.
So it seems better for if you're crowded by like, Hell Barons and Revenants and stuff, rather than against the AoD.