The planet's entire ecosystem seems consciously hostile to all foreign life. Each and every element of the native flora and fauna of the planet represents a real danger to any Human.
Catachan's only valuable resource is its people, who by virtue of being born on the harshest world in the Imperium are invariably tough and cunning. It is home to the renowned Catachan Jungle Fighters regiments of the Astra Militarum.
When the first exploratory probes arrived in its star system, the planet was a deceptive, calm green orb when scrutinized from orbit, but when the first colony ships crash-landed on the jungle planet and the colonists had no way to escape, they discovered themselves to have arrived on one of the harshest and most dangerous planetary ecosystems in the galaxy.
The colonists only barely survived, holed up in their spacecraft against a living, besieging jungle, a battle for survival in which undoubtedly many of them died before they finally managed to learn enough about their new homeworld to survive, if not thrive, beneath its jungle canopies.
In time, their skill at surviving on Catachan came to the notice of the Departmento Munitorum, which realised that the Catachans would make excellent Astra Militarum troops dedicated to service in some of the galaxy's most hostile planetary environments, and the first regiments of the Catachan Jungle Fighters were raised.
During the 13th Black Crusade of Abaddon the Despoiler in 999.M41, Catachan found itself in the path of both a wounded Void Whale and an Ork WAAAGH! led by the Freebooter Kaptain Badrukk. However due to astropathic interference caused by the Warp Storm Bas Infernia, the Imperium was unable to warn the Catachans of the threats approaching their homeworld.
After the formation of the Great Rift following the fall of Cadia in 999.M41, Catachan was caught within the malignant Warp rift and exposed to a massive daemonic invasion. However when Roboute Guilliman's Indomitus Crusade arrived at Catachan, its Astartes found that the local Catachan regiments had already dealt with the threat on their own.
Currently, the few Human settlements on Catachan which can defend against the jungle and its predators are giant fortresses surrounded by vast plains which have been laboriously cleared to provide improved lines-of-fire. Building on Catachan is difficult at best as vines and lichen take hold anywhere and poisons melt the mortar and vines can crush bunkers and tanks.
Buildings must constantly be rebuilt, for it seems that wherever the people of Catachan build structures, the jungle redoubles its efforts to destroy them.
As well as the jungle's flora, the native wildlife gather to repel the Human invaders and eventually their numbers grow large enough to push the Humans out of one fortress so they must found a new settlement elsewhere where the process will inevitably repeat itself, meaning that no Human settlement on Catachan is ever truly permanent.
Fifty percent of the planet's Human population does not survive infancy, and fifty percent of the remainder does not live past the age of ten solar years.
Every day for a Catachan is spent fighting on what is the deadliest planet in the galaxy. In such dangerous surroundings, children are quick to learn survival tactics and only those who are tough, fast and have good aim can even hope to survive into adulthood. The children of Catachan often learn to shoot before they walk, much like Cadian children.
Flora and Fauna of Catachan
All of the animals and plants of Catachan are deadly predators who have evolved potent biological attack and defense mechanisms against other lifeforms, particularly Humans. Every known Catachan plant species is toxic, making foraging for native food impossible.
Some plants secrete pollen into the air which is poisonous and destroys air-filters. Others secrete sticky liquid to capture passing animals and slowly dissolve them, much like giant Venus Fly-Traps. Some plants poison the ground and turn the immediate area around them into boggy wasteland to trap invaders.
The native animals are as deadly to Humanity as the plant life. for instance, the massive insectoid predator called the Catachan Devil possesses jaws as big as a tank and is a major threat to Human population centres on the world. The Shambling Mamorphs of the volcanic regions are also a great danger to Human settlement.
- The Brain Leaf, a vegetative carnivore, is a small tree, not particularly conspicuous on Catachan, but is able to attach its tendrils to the spine and brain of any animal, taking control over their body. This creature may actually be a genetic offshoot of the Tyranid Cortex Leech, a creature with similar abilities, that was cut off from the Hive Mind and went feral.
- The Spiker, another deadly plant, fires its spikes into its victims' bodies, which contain the Spiker's DNA and unleash a series of mutative chemical reactions which literally transforms the person into another Spiker.
- The Venus Mantrap is a carnivorous plant whose analogous species are common to many jungle Death Worlds across the galaxy. It resembles the Terran Venus Flytrap for which it is named, but is far larger, and unlike the flytrap, it is not stationary but is able to move its leaves to attack and consume its prey. The Mantrap consists of a number of mobile leaves attached to a single immobile stem.
- The branches of the Spore Tree hold dangling flowers which launch a cloud of spores when they detect something moving close by, to carry their seeds to other fertile areas. The spore cloud is so dense that the creature which disturbed the tree often chokes and dies. This is also useful for the Spore Tree as its victim's decaying body will enrich the ground around its roots.
- The Strangleplant prefers shady spots to grow in, where its distinctive tube-like trunk is hidden from view. When it detects the air disturbance caused by a passing animal, its long, highly adhesive stamen uncoils, wrapping itself around the prey and dragging them back to die of dehydration.
- The Canak Floater is a bizarre and deadly plant filled with lighter-than-air gases, and it drifts across the planet with the vagaries of the wind. It has sensitive feeler tentacles, which detects warmth and moisture above the normal local levels. This is usually to uncover streams, hot springs and other sources of water, but unfortunately is also sensitive enough to detect the temperature of and moisture changes caused by Humans. When it finds such a place, the floater explodes, scattering its seed pods over a wide area. These seed pods have a diamond-hard outer casing with razor sharp edges, and will scythe through anything within range.
- The Miral Catcher is a ground-hugging vegetation which has roots that are extremely sensitive to vibrations in the ground, such as might be caused by an animal wandering past. It looks innocuous enough when dormant, but when it attacks, huge tentacles whip from its many frilled maws and lash out. They carry a paralysing toxin, which acts almost instantaneously upon the prey.
- The Sucker Tree is a plant that is fairly innocuous looking to the untrained eye; it is simply a fungal-like growth on top of a seemingly normal trunk. However, the trunk can twist and turn when it detects prey, bending over to drop its suckers on top of the heads of its victims. It quickly drains them of their life fluids and then flings the corpse away to ensure that future victims are not made suspicious by a pile of bodies.
- The Spitting Cactus is a deadly form of jungle cacti, and is able to fire toxin-coated spines directly at nearby prey.
- The Catachan Mantrap is a plant which, while having a similar name to the Venus Mantrap, uses a much more aggressive hunting technique. It can move its leaves around, actively searching out prey and clamping its jaw-like leaves around its victims.
- The Stranglevine
- One of the most famous deadly animals of Catachan is the Catachan Devil, a voracious insectoid predator, looking somewhat like a many-limbed Terran scorpion or centipede. They can be as long as a land train but are very bulky and slow-moving, which means that escape is possible for the unlucky Humans who confront one.
- The great quadrupeds called Grox, although originally native to the Soloman System, are also found on Catachan, perhaps brought by the early Human colonists. The animals are prized for their highly nutritious and tasty meat, and have been introduced to many worlds throughout the galaxy, so that the Grox is now the most ubiquitous livestock animal in the Imperium. The Grox however are extremely ornery and virtually impossible to keep under control without some form of brain-implants or lobotomy - on Catachan they have become wild, and are deadly predators. Grox are used by a galaxy-spanning food consortium to produce the famous 'Grox Burgers'.
- The Shambling Mamorphs of the volcano lands are tough fighters and put up a good fight even against the Catachan Devil.
- There are also many types of reptiloid serpents on Catachan, including the Flying Swamp Mamba, the Coiling Death Cobra and the Catachan Black Viper, and all are deadly to most living beings. Some have toxin that is so powerful it can kill in under 30 heartbeats.
- Great Barking Toads, although appearing benign and harmless, are literally volatile creatures: the creature is easily startled, and anything it finds threatening is liable to cause it to explode in a cloud of toxins which kills anything within a very wide (one-kilometer) area, including the Barking Toad itself. The Barking Toad toxin is virulent enough that even respirators and sealed suits such as power armour offer no protection, and no other known substance can halt its destruction. They are known as the most toxic creatures in the galaxy.
- Blood Wasps are swarms of small, deadly insects that are known to eat their prey alive, stripping them to the bone in under an hour.
- Heretic-Ants are named on the account that they always attack their prey's feet (or "Soles") first. One bite from these insects will put a fully grown man in the infirmary for a month, two bites will give them around a day to find treatment before dying, and three will simply kill them outright.
- Vein Worms secrete an ooze that numbs their prey when they bite, so that they cannot feel a thing. The Worms then dig their way under their prey's skin and into the bloodstream to lay their eggs. The eggs will spread all around the host's body, and when the larvae hatch they will eat their way through the host's brain, heart and bones. There is no known cure for Vein Worms once they have entered the bloodstream.
- Drakebats are Ogryn-sized, winged, pseudo-reptiles that lurk amongst the upper canopy of the equatorial jungles of Catachan, descending from the treetops to ambush and devour unsuspecting prey.
- Death Flies
- Catachan Water-drakes
- Catachan Bloodflies
- Catachan Pusworms
- Spinebore Leeches
Incidence of Disease
The threat of disease is also a constant hazard on Catachan, as there are many varieties of poxes and fevers that can kill a man within a few solar hours due to the world's fecund microbiosphere. Many of the planet's native insects also carry virulent diseases on top of being poisonous, meaning that a single bite can be lethal in more ways than one.
The world does not just breed diseases in its fauna. Most of the more virulent microbes cannot be seen at all, floating through the air until they find a host and enter their bloodstream. There are lethal swamps where a single breath of the fog will burn an intruder's lungs out, causing a long and agonising death.
Even the water on Catachan can prove fatal to drink as diseases and poisons flow through it. Foot Rot can occur after just a few solar weeks within the jungle, where the rotten feet will detach from the host's legs, producing a vomit-inducing stench. As such, many Catachans consider disease to be a greater enemy than any beast or man-eating plant.
- Codex: Astra Militarum (6th Edition) (Digital Edition), "Regiments of Distinction - Catachan Jungle Fighters"
- Codex: Imperial Guard (5th Edition), pp. 27, 64
- Codex: Imperial Guard (3rd Edition, 2nd Codex), pg. 60
- Warhammer 40,000 Chapter Approved - The Book of the Astronomican, "Introduction," pg. 1
- Warhammer 40,000: Rogue Trader (1st Edition), pp. 1, 212
- White Dwarf 388 (UK), pg. 77
- Gathering Storm - Part II - Fracture of Biel-Tan (7th Edition), Chapter 2: Empire of Ash, "Intervox Mechanicus" (Sidebar)
- Codex Adeptus Astartes - Space Marines (8th Edition), pg. 20
- Codex: Imperial Guard (5th Edition), pg. 15
- Only War Core Rulebook (RPG), pp. 44-45
- Straken (Novel) by Toby Frost, Chs. 4, 12
- White Dwarf 242 (UK), pp. 81-85
- White Dwarf 286 (US), pp. 104-106
- Death World (Novel) by Steve Lyons, pp. 71, 94, 136