Haha wow, the best way is 5 people with ghorn if you don't have a party full of horns the next best is to use snipers and heavy machine guns, people that use rockets and grenades and supers are making him move while the rest of the team are being screwed because he moves, hard mode atheon can be take down in 2 portal passes with snipers and heavy machine guns anything other than those weapons is only hurting the rest of the team