However, much like the Aurans themselves, you can take the beast out of the wild, but you cannot take the wild out of the beast. Powerful talons and scales make them able combatants, whilst their charge is strong enough to knock over even a fully armoured Space Marine.
So strong is a given Theratryx that they can even be ridden by the same Astartes. This strength can be seen in their fleetness of foot, their every step silent despite their bulk.
- Deathwatch: The Emperor Protects (RPG), pp. 16, 25, 50