You need a bunch of good tanks, main tank, then a back up for the tank, etc. especially since Zaken ports you around various rooms of the ship, having an extra few tanks would never hurt. at least 3 real good tanks, and a a whole bunch of nukers, bladedancers and rechargers for the nukers as zaken drains mp, among other things
also you can not kill Zaken at night as he'll be all but invincible.
since nobody has the B@LLS to reveal the secret to taking Zaken, we might as well say you need to have everyone level 1 with Reflect Damage buffs. send in the army, watch them die, watch Zaken kill himself.