I think that Ghaul (post Homecoming) is several time stronger than oryx and other creature in the Universe. Start with a comparation Traveler power=Deep power. The Traveler power is now concentrated in the hands of ghaul. The Deep power is divided in 5 worms god: Akka Yul Eir Ur Xol. We know that oryx eated Akka and with a good probability not only he. So if We put Ghaul at 10 Teo a scale of power, Oryx will be 2 or Max 6. So Oryx, a extremly powerful creature will be a little sh1t compared to the Emperor