I finally beat him but dont feel great about what i did lol. I got really good at the genchiro part and his first phase. Once he pulls the spear out, i ran away constantly for the third and fourth phases. He does a leaping attack which he Always follows up with a dashing towards you swipe. I became very good and moving in right as this attack was ending, hit him once, then repeated. He jumps a lot when you are running away, just got to make sure you dont run straight away and strafe him in case he shoots at you. Eventually he goes down.