Hardmode added a new element to the Oryx fight. 4 "Light-eater" knights now spawn as you kill the ogres, and they try to eat the bombs like the Vessel does. People are now running a strategy that involves leaving the ogres alive and allowing them to go to the middle (since the knights don't spawn until you start killing ogres), staggering Oryx, and then killing the ogres and jumping into the bombs. The knights will spawn then, but they won't have enough time to get to the lights. People disagree about whether or not that's a legitimate strategy.