Oryx was killed in the "Regicide" campaign mission. Concluding that arc. I didn't have to play the raid to know I killed him. But let's say we didn't kill Ghaul in the story, then the next DLC comes out & I didn't play the raid to kill him, but he's not a threat anymore, no one seems to care about him even though he destroyed our city. Where did he go? Oh! He was killed in the raid I didn't do? Well, I'm glad I pursued him for the entirety of the campaign just to never kill him.