It actually doesn't do fire damage, but physical and lightning damage. PDR / DR% can help a lot, PDR even more so I guess because it hits every few frames. Shield can also block the physical damage part.Try to get your lightning and fire res as high as possible.
Sorry, yeah, that is what I meant. Fire damage from his other attacks.It actually doesn't do fire damage, but physical and lightning damage ...
Although I guess you're right in having fire resistance helps against Diablo in general considering his other attacks.
Not in normal mode, however. It would be helpful to find out which gesture he makes before he's breathing or spilling fire.And yes, standing really close to him helps for the lightning hose attack.
Agree, you've got to keep your space with him in norm, especially on higher /plvl.In Normal, I usually prefer to keep a healty distance. I've killed him with things like Fiery Pilum (bought from Jamella) and plain Throw, both with Assassin, Amazon and Paladin. Several repairs needed, but reasonably safe.