Diablo 1 HD Hellfire Mod | Awake

I´m facing it as sorc on Hell atm, needless to say it shreds my 3800HP golem in seconds and is quite hard to kill.
Would be way easier if it wouldn't constantly heal itself (or in this case, be immune to fire, so no guardians).
About the healing, is it a spell it just casts from time to time, or does it actually have something like a mana pool behind that can be empty or regenerate?
Tried covering it in countless blizzards, it does damage, but it just heals every few seconds so no gain...

EDIT: yay got him without fire resistance now. still, guardians do about no dmg to him...

Does insanity work on sorc and his speed of casting spells?

I had simillar problem with my rogue, I tried to move around using golem / teleport / arrows but in the end he would just heal the damage. I drank 4 potions, cast insanity, and went all in. And it worked. Funny thing is that the situation i described happened at hell difficulty, while at torment i had no problems at all with defeating him.

The fallen hero is a revenant weak against holy bolt

oh, thats very good to know.
i killed him in the end with elemental drain and massive blizzards though.
holy bolts would certainly have been easier...

With elemental drain he's easy cake with Guardians on every difficulty ^^