Quote:so she shouldn't take much damage if she's got max resists, you didn't mention difficulty or level though?
Well, I rechecked -- my merc is now lvl 81 (was lower previously -- but everything was on hell difficulty, mostly in durance) with 1265 life.
She had a Dark Adeherent Dusk Shroud on that gave her some fire resists (57%).
After taking off the shroud (giving her 33% FR), I believe I could see her taking a little bit of damage from standing in a firewall and being hit by several fireballs. From your figures, one firewall would inflict 33 da/sec and her regen would be about 31 hps/sec, so it is a very marginal test. It does seem that she's not immune to elemental attacks, but she still appears to take less elemental da than you'd expect.
I dropped in on Nihalthak (also on hell diff) and his corpse explosions didn't do any damage at all. I was standing in a pile of corpses and could see them pop but I wasn't hurt. It made the quest a lot easier to complete, so maybe this is one bug that shouldn't be reported. ;) I don't know if it's connected with the apparent lack of damage from doll explosions or not.
p.s. This is all 1.10s