Oryx, like all hive, gains his power from a symbiotic species of worm living in his head. Oryx is just one of the first hive to meld with the worms. In doing so he was granted a long life (naturally hive only live to be about 10 years old), space magic and the secrets of the universe.

I'm asking this out of curiosity: but I thought grimore described hive as being like fossils specifically knights. The taken knight card talks about "centuries of slaughter" if I recall, as well as the original description of the hive. Is this just for all hives without worms?

All hive that made it off their home world have worms. Find calcified fragments on the dreadnought to unlock the book of sorrows grimoire cards, it details the early history of the hive. Here's what I've got from the first 23/50, if you're interested. [spoiler]The hive lived on a planet they call fundament. They were a sentient, if barbaric, insectile race. They seem to have lived on tectonic plates floating inside a gas giant. Each plate holds its own society/kingdom who are always at war with each other whilst being hunted by predators both high in the clouds and deep below their continents. The cards make out that all hive are born as thrall, developing into acolytes until their coming of age which would have been at about 4 years old, when they become Knights and wizards, with knights being the male of the species and wizards being the female. Knights, princes and normal hive only lived to be about 10 whilst wizards, through the act of mating and spawning, were granted slightly extended lives. The ruler of the kingdom known as the osmium throne is killed by a rival kingdom and his daughters are exiled. In exile two of them vow revenge on their conquerors whilst the third, Aurash, is driven by a thirst for knowledge. They discover their "mad" father wasn't entirely mad. He'd discovered that someone, somehow, had changed the orbits of the 50 or so moons of fundament so they would line up in a few years, creating a massive tidal surge that would wipe out all life at their level of fundament. After two years in exile, at about four years old, they find and repair a space ship but are compelled to travel deeper into the planet. In the core they discover the worms. The worms convince the three sisters to bond with them, bribing them with power, knowledge and immortality. Aurash accepts for the immortality so she can keep on learning, whilst the other two accept the worms for the power to avenge their father. They all change their names to reflect their new identities, with Aurash becoming Auryx (Oryx). Sometime later, after wiping out most life on fundament, there's a small civil war between the three sisters. Auryx doesn't want to kill anymore. It's at this time they discover the downside to bonding with the worms. The worms crave, no, need conflict. They absorb the life from those they conquered and every sacrifice of life energy means a bigger one is needed next time. It's around this time that Auryx stops being a just scholar and starts his/her own quest for power and death. The worms teach the sisters how to make technology to allow them to leave fundament (they've been living on fundaments moons throughout the civil war). The sisters decide that the natural order of the universe is chaos. Civilisation is order. Therefor civilisation must fall. They also decide that they must fight amongst themselves to increase their power, hone their skills and also to keep things chaotic. Somewhere in the first civil war, one of the sisters "kills" another by blowing up the moon they're hiding on. It's in this "death" they discover the pocket realms Oryx takes the taken to to change them Each of the sisters creates her own realm. By implanting their broods with worms they not only increase the power of their armies, they have the ability to control their development. Now, only those who prove themselves get to become knights and wizards. By over feeding the worms inside thrall they can create ogres. The hive go out into the stars, destroying entire sectors of the galaxy in their battles amongst themselves. Eventually they discover a race known as "ammonites", who are protected by the traveler. They descend upon the ammonite home world and the traveler flees. [/spoiler]