Great Guardian fight is literally killing me

[Nalayar]

I've been trying to kill this huge automaton many times and have failed each time. First of all you lose an entire turn just getting to him, so you're a sitting duck for the several (is there four of them) smaller automatons to breathe fire and slice my party up. And of course the big guy is shooting fire and lightening at my party too. One usually dies right away.
I tried having my rouge (Sebille) sneak and try to pickpocket the phase capacitors out of the smaller ones. It worked once and then a fight started, she was overwhelmed by several of the smaller automatons, and died on the far side of the big guy.
I even respeced my party for this fight but it didn't seem to help.
I killed all the magisters and Black Ring on Nameless Island, the Shadow Prince, Alexander and his party, and never had problems like this with a fight (and someone mentioned on one of the forums, not this one, that this fight wasn't difficult).
Any strategy that I'm missing would be helpful. I tried in respecing to buff my spell casting (get '5s' in Aero, Scoundrel, Pyro, Hydo, Necromancer, Hunt, Geo, and Poly) so I could use the more powerful spells, but maybe this strategy isn't the best as it's not working).
Thanks for any input.

[Chaoslink]

Look at the damage types you're taking. Fire. Lightning. Drink some Resistance potions and suddenly you'll be taking very little damage.

I don't remember the specifics of this fight to be honest, I vaguely remember there being extra mechanics regarding stuff in the room, but I don't remember.

[BOT]

sneak jump into the room..
hide in a corner..
start fight with a second guy and swich back to your stealing sneaking guy.
stay always in sneak mode. steal the capasitator. ez fight.

or arange the mirrows correct. halfway ez fight..

or fight and use your godly powers and use resist death if needed.. go invisible.. teleport .. use scrolls and potions.. doo all sort of things..

those fights are not ment to be spell fights.. they are ment to be use your creative brain fights.

[Nalayar]

I should have waited to post this. I won the fight; I first killed all the minor automatons. There were three left after I removed the capacitor from the fourth. After that all four of my party took on the Guardian and killed him.
The Arena of the One was a real pain..not the fights which I had no issue with, but with the falling lava. Two of my party died and lava fell on their bodies, and I couldn't reincarnate them as they died immediately again as they were in the lava.
Had to teleport their bodies out of the lava and then reincarnate them.
Really thought I was going to lose that battle because of the lava falling.