To be honest, the best way to beat him in the end game, is to dodge a lot! Dodge him and throw stuff at him, and go in for hits when the triangle prompt pops up. Once he starts throwing the waves of his guys at you, they are basically one shot. Beat one, then dodge, beat one then dodge, over and over until he brings out his huge armor guy. With him, swing around because his attacks are ground based. Once he disappears just use the triangle prompt to beat him. Rinse and repeat and it's a decently easy boss fight. Thanks for reading!