Single Player: Before you go out to fight him pick up the Torque Bow and either the Sniper or Lancer and make sure you have full grenades.
To start off take cover behind the cover right in front of you, fire a Torque shot into him and it will dissipate his kryll shield, then switch to your lancer/ sniper and let loose on him until his kryll shield comes back. Then rinse and repeat, if you run out of torque shots use your grenades and when he gets up to the cover your at, book it to the other side if it comes to that.
Co-op: Pretty much the same thing except each person can take their weapon of choice. One with torque, other with sniper/lancer, it is a lot easier this way, but if you cant find a partner just follow the above solution and you should do fine.