Catachan is the most infamous death world in the galaxy. It is located in the Ultima Segmentum[3a] and is covered in dense jungle. 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 Imperial Guard.
|Map||Basic Data||Planetary Image|
|Class:||Death World, Jungle World|
|Tithe Grade:||Solutio Primus|
Catachan was colonized by humans longer than Imperial records can remember. When the first probes arrived, the planet was a deceptive, calm green orb from orbit but when the colony ships crash-landed and the colonists had no way to escape, they awoke to find themselves on one of the harshest planets in the galaxy. The colonists only barely survived, holed up in their spacecraft against a living, besieging jungle, a battle for survival in which many undoubtedly died.
Currently, the few settlements which can hold back the jungle forces are giant fortresses surrounded by vast plains which have been cleared to give improved lines-of-fire. Building on Catachan is difficult as vines and lichen take hold anywhere and poisons melt the mortar and vines can crush bunkers and tanks. Buildings must constantly be rebuilt; it seems that wherever they build, the jungle redoubles its efforts to destroy them. As well as the jungle, the native wildlife gather to repel the human invaders and eventually the numbers grow enough to push the humans out of their settlement so they must resettle elsewhere.[Needs Citation]
In such dangerous surroundings, children are quick to learn survival tactics and only those who are fast and have a good natural aim survive to adulthood. Children often learn to shoot before they walk, much like Cadian children.[Needs Citation]
Flora and fauna
All of the animals and plants on Catachan are geared in some way to destroy humans and any other invaders. Every plant is poisonous, making foraging 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. Other 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. The native Catachan Devil with jaws as big as a tank is a major threat to human living centres. The Shambling Mamorphs of the volcanic regions are also a major threat.
- The Brainleaf, 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 a person, taking control over their body. This creature may be an offshoot of the Tyranid Cortex Leech, a creature with similar abilities.
- The Spiker, another deadly plant, fires its spikes into its victims' bodies, which then releases a mutative chemical which literally turns the person into another spiker.
- The Venus Mantrap is a carnivorous plant common to jungle Deathworlds. It resembles the Terran Venus Flytrap for which it is named, but is far larger, and unlike the flytrap, it 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.
- Grox: although originally native to the Soloman system, 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. 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.
- Shambling Mamorphs of the volcano lands are tough fighters and put up a good fight even against the Catachan Devil.
- Catachan Devils are voracious predators, looking somewhat like many-limbed scorpions. They can be as long as a land train but are very bulky and slow moving, meaning that escape is possible.
- There are also many types of serpents on Catachan, including the Flying Swamp Mamba, the Coiling Death Cobra and the Catachan Black Viper, and are all deadly to most living beings. Some can kill in under 30 heartbeats.
- Catachan Barking Toads: although appearing benign and harmless, the Great Barking Toads are arguably Catachan's deadliest animals: the creatures are easily startled and, whenever they feel threatened, explode in a cloud of toxins which kills anything within a one kilometer radius, including the Barking Toad itself. The toxin is virulent enough that even respirators and sealed suits such as power armour offer no protection. They are known as the most toxic creatures in the galaxy.
- Catachan Water-drake [8a]
- Catachan Bloodfly [8b]
- Catachan Pusworm 
The people of Catachan are not only hardy, but pragmatic, with an easy grasp of realities and an uncomplicated attitude towards danger. They are also somewhat disdainful towards people from other worlds, believing - with good reason - that few others in the galaxy have had an upbringing as dangerous as their own.[3b]
- 1: Codex: Imperial Guard (2nd Edition), [Needs Citation]
- 2: Warhammer 40,000: Rogue Trader, [Needs Citation]
- 3: Codex: Imperial Guard (5th Edition)
- 4: Warhammer 40,000 Chapter Approved - The Book of the Astronomican (1988), Introduction
- 5: White Dwarf 388 (UK), p. 77
- 6: The Killing Ground (Novel) by Graham McNeill, Prologue
- 7: Waiting Death (Short Story) by Steve Lyons
- 8: Straken (Novel) by Toby Frost
- 9: Rebel Winter (Novel) by Steve Parker, Chapter 3