Okay, warning rant incoming:
How are you supposed to ever deal damage to him. He CONSTANTLY spawns new Minions and Act Bosses who make him immune to all damage and there are only so many corners you can lure him into until you have to kill the Bosses. Additionaly he has his dumb normal Minions which are also tanky as fuck and teleport on top of you everywhere you go. And i refuse to believe that my 67-72k damage with 150poison pierce Spearzon "just doesn't deal enough damage".
This fight is the purest meaning of RNG if he never stops summoning adds. Make him summon like a wave of minions and a boss at certain health tresholds and maybe make the bosses tankier in exchange, but pls remove the RNG from this fight where you basically never get to damage the boss.
Rant over.
But seriously, what else should i do. Do i need even more damage? I have the SU Maiden Spear with full Posion runes as weapon and as stated am sitting at 150% pp.