Drop in from waterfall, clear your way to the suspended tracks. Take the wooden ledge to the left and he spawns down that short hall, close to the end before the dropoff. There will be 3 spawns, and 1 roamer, 1 on the wooden ledge. He is the left most spawn location.
Not to be nitpicky..but to make it a bit more clear...if you are looking to toards the edge of the drop-off, his spawn in front on the right. Not that it would matter anyway...anyone doing this camp would clear out all the mobs anyway.
Ive killed him 5 times, my friend said he killed him 6 times, and out of those 11 times he was killed, the trident dropped once.....so that would leave to say that the trident is his rare drop
His lvl is off. I've killed him twice and he's been green to a lvl 60 both times. He's a SK. He's dropped each item for me, so I don't know which is the rare one.