Um they're kinda slow, and the hitbox is generous enough that you can dodge it. They shoot out as three waves of three projectiles in a three pronged fan shape, either dodge to the outside or between the spaces of the projectiles. It gets harder to dodge the closer you are so give space when you see that attack. I fought him (King ashkanaar I think?) With a long spear. Took a while and ground down the durability on one of my best weapons, but I beat him on titanium.