Oryx fight does not require you to kill the orges to stagger him. (Which is the most important) Or to kill the vessel to stagger him (vessel works as a light eater) Those knights still do spawn after the orges dies. You're just getting there before they do anyway. No one said you had to kill them because they despawn after the bombs. Even if a light eater steals a bomb. As long as you get 1 bomb off. Oryx takes damage (of course this draws the fight out)