You should have bought the sword of justice from the blocksmith in acm city,It helped me beat it.
I would recommend the Stronghold Sword because it helped me through many levels.
You know, that sword on the table in the Kalphiters Guildhall? Yeh that's the Stronghold Sword
I believe that's the Avatar Golem you're fighting there. Not the final boss. Keep playing and you just might get to him!