Only need 2 nin and you can beat him.
Though, he got Stun and if he uses his boost attack after that and the nin, or anyone, doesnt have shadows up... poof, 1000+ damage.
He can be slept, but he will start resisting after 2-3 times. And he resist mosts debuffs, just let the nins use their debuffs for hate and everyone else sub nin or whm for blink.
Hes pretty easy, but if you do one mistake you are dead, just die close to the portal with reraise, or let a raise go trough the portal and then back in to start over.