Thanks for the feedback! I thought the same as well about what Oryx's Worm feeds on, but Calcified Fragment: Carved in Ruin says that after the death of Akka, the siblings fed on Killing instead of their individual traits. This is why they had to seperate because before they could each take what they needed from their individual Worm, but after they decided on a tribute flow their Worms all fed on the same thing.