Max hit is a hell of a lot more then 6400. He gets stronger the long he's on on target, after 10 seconds he's hitting for 7k+
One of the few fights ping pong aggro is ok.
Hits for ~6400 (increases from there the longer he is on one target); summons; single-target rampages; enrages.
Sees invisibility; does not see Shroud of Stealth; immune to snare/root/mez/stun.
A Shell of the Master spawns with loot following its death.