"The rain may dissolve your goggles, but trust me, you want to keep looking up. That’s where the worst of them come from."
- — Krellen Fosse, Calixian Beast House Procurer
The Terrorax is literally one of the higher predators in this hellish environment of Burnscour, living in the verdant canopies of the thick jungles that cover much of the planet. It can grow to huge sizes, with legs spreading six metres across, and is strong enough to carry a fully laden Imperial Guardsman into the arboreal heights with ease. Its bulky reptilian body is protected with heavy chitin plating, as are the six long spider-like legs and two huge pincer claws mounted at the front of the body. This thick armour is sufficient to withstand the frequent corrosive downpours as well as most small weapons fire.
Typically, the creature uses its powerful fore-claws to grab and hold its prey, either crushing or tearing the doomed creature into submission. Witnesses have reported these claws able to cut off the limbs of Ogryn warriors and rip apart suits of heavy power armour. That there are few who doubt such reports speaks to the creature’s ferocious reputation amongst veteran xenographers operating in the Koronus Expanse. The head is covered with a lesser layer of toughened skin, but some reports indicate it can be retracted into the central carapace when the rains or larger predators become too threatening. The wide jaw contains rows of serrated fangs, used to devour its exclusive diet of fresh meat, and extends far along both sides of the head allowing it to make huge, devastating bites from captured prey. The eyes are large and featureless underneath chitin, reflecting slightly in a soft gleam in the shadowy lower areas of the jungle.
The multiple lower legs, however, are the primary method for locating new meals. Each of the long, stalklike limbs contains powerful sensory nerves and can detect minute vibrations transmitted through the ground and trees. The creature can pick up signals indicating far-away prey in the dense jungle merely by resting a leg on a tree branch. This detection system is superior in many ways to visual or even olfactory senses, given the cluttered nature of Burnscour’s landscape and multitudes of camouflaged lifeforms, many of which have disguised scents.
The sharp spikes at the end of each of these legs also make for deadly weapons, and can stab into flesh as easily as they stab into tree trunks to anchor the Terrorax as it moves across the foliage above the ground. While not as powerfully muscled or armoured as the fore-claws, they can punch out with surprising speed in many directions, striking at any creatures seeking to surround the beast.
The Terrorax is a quiet and patient hunter, scuttling without any sound across the foliage in constant search for prey. It is also incredibly agile, and is able to dart up and down jungle limbs as well as leap from one tree to the next with ease. Most of the time the fleshy head is almost totally retracted, protruding just enough so it can see. When not needed the heavy fore-claws are also rolled back so they do not interfere with the hunt. It alternates rapid movement, ranging from a short distance along a branch to dozens of metres to a new tree, with short pauses to sense any nearby prey. Each pause allows it to use its sense of touch, via the nerves in each leg. Its highly-evolved sense of touch filters out rainfall and other natural patterns, allowing the creature to seek out any animal life moving below on the ground. Once a new victim’s location is approximately determined, it moves closer until the prey is in sight.
When the quarry is visible, the Terrorax freezes into stillness to observe. The armoured plating has a mottled green and brown coloration and blends into the surrounding plant life, along with a rough texture that aids in the camouflage. Each of the long legs can easily be taken for a tree branch unless closely examined. It can remain in this state for long periods, preferring to wait until the prey moves into a location suitable for the attack. If the target is moving, the Terrorax slowly stalks the unknowing victim, keeping it in sight and patiently waiting an opportune moment.
Once the quarry is in an ideal location, the Terrorax slowly moves into place, one leg rising and falling at a time with deliberate and unnerving grace for a creature of its size. When it is ready, it springs down with speed and agility that belies its bulk. It can run down a stalk faster than it would fall, but can also simply leap down if the prey is too far from a trunk. Sometimes it refuses to wait for the prey to attain such a position, especially if it is overcome by hunger or an especially worthy morsel presents itself. In such cases, the Terrorax simply accelerates and goes for a faster but more risky attack. Claws are quickly extended and ideally seize the prey with a deadly embrace; this is usually enough to kill or sufficiently wound the victim. The talon legs can also be used as part of the attack, and are able to easily puncture skin and many armours with deeply penetrating wounds.
The Terrorax prefers to make lightning fast strikes designed to cripple the prey, but if needed can fight on the ground against a determined foe. If the victim puts up too much of a fight, the Terrorax often temporarily retreats back into the trees and makes ready for another attack. Captured prey, either dead or still alive, is quickly taken back up the stalks to be safely consumed away from other possible predators. Few can withstand the power of its claws, and the grounds below Terrorax lairs are strewn with cracked carapace plates and ruined power armour. After the claws crack apart the victim, meat is serrated and fed into the maw, where powerful jaws and teeth devour the flesh. Once fed, a Terrorax often climbs into a secluded location in the trees to digest its meal, but stays on constant guard as most predators know this is the time when it would be most vulnerable. Even in this state, however, only the most desperate or foolhardy would dare attack a Terrorax. Burnscour is littered with the corpses of those, both animal and human, who thought themselves ready to face this monster.
- Rogue Trader: The Koronus Bestiary (RPG), pp. 28-29