Not… the hardest, but he is the most unoptimized boss, I experience less than 10 FPS on a beefy system in some cases.
It’s best to fight him with another person, or find a way to cheese him.
imma use greatbow to cheese him then
Eh I didn’t get many performance problems but the guy kept resetting for some reason and I wasn’t even using stealth.
8 power 
thats your issue right there, you have pillow fists
Nah i won
But youd struggle less if you had more power
power schmower.
1, kite kite kite, you’re gonna have to keep dodging his attacks. It’s not worth standing to get extra damage in, stay on the move
2, use spirit hound for spirit class, flying phoenix for weapons, javelin/array/cannon/conjure elemental for magic and axe slash/shot for strength (preferrably cfist)
3, when you see the big sword nuke attack just run to the edge, attack him once every 5 seconds or so to make sure he doesnt despawn
4, with the placed explosions you just need to time your dash ~0.5 seconds after the circle appears to dodge out of the way
anything that doesnt do terrain damage (like guns) are not good since the terrain frequently gets leveled
also the albino bird (seafaring talent) works wonders since its free reinforcements, they might take a bit to arrive tho
ngl that build is horrendous
what i used is either all rounder (100 stats in all except the new ones, also defense is 300), pseudo max power (257 power) or pseudo max regen (772 regen)
first and last is with spirit hound spam and was generally just painful, the pseudo max power worked purely because i was playing metal-light mage