Currently running a
Thalore Archimage.
Despite the experience penalty, i took a Thalore to help with the summon treants from their racial tree
I decided from the start to make that character a pure Tempest, only getting manathrust to add to my firepower in case the enemy was 100% lightning protected.
During the whole early game it wasn't easy as the archimage was a bit squishy, but it was still doable with the more and more powerfull lightning spells (as i was slowly maxing them)
Then roughly between the end of the tier 2 dungeons up to Dreadfell start it was insanely hard, i lost several lives, the lack of levels (Thalore feel like playing with Skeletons on that slow leveling) was really felt but the problem was actually something else entirely :
At some point of my tier 2 dungeon clearing, i found the Staff of Destruction, it was great at that point of the game as it added +15% spell crits, lots of spellpower, and it haf 10% of launching Impending Doom (though only level 1 unfortunately) on the enemy at spell hits.
I had never used it before because by the time i found it earlier, everytime i had something better already, but not this time so i equiped it.
And then the game became insanely hard. I was wondering at some point how it was possible for my character to lose so much health during the fights, and barely getting any despite the many healing (arcane healing spell, regen, healing light from escort)
And looking at the logs i understood why it was that insanely hard.
It looks like the random generation on the enemy in that run seems to put some reflection shield to at least 1 out of 5 monsters ... leading basically 20% of my battles ending with my character affected by my own Impending Doom !
Once i switched to something else after discovering that, the battles became much more reasonnable.
I'm now in the East, my Tempest is now really starting to feel powerfull as he has several important lightning and storm skill maxed (there's a great synergy between some sustains of those trees and their skills), lots of his lightning spell can now daze and trigger the hurricane effect, he has high lightning penetration (so those pesky 100% res monsters can still get their bottom handed to them) and as i just hit level 30 i decided to choose the Meteor prodigy to add some more overkill damage