It's currently possible to solo this boss, as a hunter(havn't tried with any other classes), even though he kills you during the fight.
Requirements; Trap Launcher & Snake Trap & Somewhat decent gear.
How To:
Pop all your cds and nuke the boss as hard as you can.
At around 15 seconds into the fight, he'll oneshot you.
He would normally despawn now.
BUT --->
If you time your snaketrap(glyphed), he'll "kill" these, while the spirit ghost attempts to ress you.
Rinse and repeat till the boss is dead.
-> i havn't tried with the cardboard dummy