An Ambull is a massively built, roughly humanoid xenos creature with an insect-like armoured carapace and oversized arms tipped with iron-hard claws. Their pronounced hunched stance lowers their true height greatly, but when fully upright with claws stretched overhead they can easily reach four metres in height.
Ambulls are extremely hardy and long-lived social creatures, usually forming close-knit family units with several adults tending to broods of four to seven offspring. They are also natural tunnelers, with eyes sensitive to the faintest light even into the infrared spectrum, and claws that can excavate through soft rock and earth at alarming speeds.
Ambull communal tunnels and caverns can stretch for many kilometres underground, forming a vast network of what can appear to the unwary as safe havens from threats above the ground.
Most Imperial xenologists believe the species evolved in the deserts of the distant Death World of Luther McIntyre IX in the Segmentum Tempestus. There, Ambulls primarily live underground during the harsh local days, emerging at night (sometimes in packs) to scavenge and hunt, but also stalking any underground prey through their networks of tunnels.
Due to the intense heat of Luther McIntyre's sun, the Ambull's subterranean lifestyle is shared with many of the Death World's inhabitants, including the Ambull's favoured prey, the Crawler. Ambulls will pursue their quarry through soft rock by tunneling at considerable speed.
They can burst out of the ground upon their victims and smash with their huge arms, devouring flesh with their great, razor-edged mandibles. Often they will drag the insensate body back to their burrow-nodes for the group to feed upon, especially immature Ambulls still learning how to hunt on their own. Ambulls favour live prey but are capable of eating almost anything they encounter.
Despite Delta-level bans on their transport, many ill–informed but ambitious groups (ranging from wealthy nobles to forbidden cults) have endeavoured to import and domesticate them as attack creatures or compound guards.
Even when working with immature specimens, these attempts have always proved disastrous (often spectacularly so), usually resulting in groups of Ambulls escaping captivity to breed on their new planetary home. As a result, Ambulls have become common on many planets with desert conditions across the galaxy.
As almost any environment is less hostile than their native one and their new local prey both more plentiful and easier to hunt, they are known to breed at alarming rates and quickly become dangerous threats. One thing that Imperial xenologists have noted is that no matter where they are found, Ambulls show no sign of genetic drift or other morphologic changes.
Even in the harshest, most radiological or polluted environments, these creatures remain unchanged, other than expected variations in colouring. Their extreme genetic stability in the face of mutation has been the subject of several intensive studies but with inconclusive results so far.
The more radical elements of the Adeptus Mechanicus' Magos Biologis even propose that the Ambull may represent an engineered breed designed to withstand Chaos. Wiser Adepts believe they are simply the result of the intense struggle for survival on their native hellish planet.
Ambulls were sighted on the Ice World of Simia Orichalcae while the 597th Valhallan Ice Warriors Regiment of the Astra Militarum was tasked with protecting a valuable promethium refinery. It was later believed that the creatures arrived on that world through a Warp portal opened from some unknown Desert World by a force of Necrons that was carrying out a reconnassaince mission on Simia Orichalcae.
These Ambulls killed several promethium miners in the lower tunnels, while Commissar Ciaphas Cain and a Valhallan scouting party slew a great number of the beasts in the tunnels. These Ambulls were able to tunnel through ice as easily as sand or rock, and proved extremely hardy even in such a radically different environment from their preferred arid biomes.
After the Simia Orichalcae campaign, Cain dined with Inquisitor Amberley Vail at an upscale hotel, which offered Ambull steaks as a room-service menu item. The Tech-priest Logash had earlier told Ferik Jurgen, Cain's Valhallan aide, that Ambull meat tasted much like that of grox.
The 1st Edition Warhammer 40,000: Rogue Trader rulebook (1987) stated that Ambulls might have originated on the Death World of Luther McIntyre IX in the Segmentum Solar, but the Liber Xenologis (2021) instead claimed it to be the Death World of Luther McIntyre IX in the Segmentum Tempestus.
- Dark Heresy: Creatures Anathema (RPG), pg. 51
- Warhammer 40,000: Rogue Trader (1st Edition), pg. 207
- Warhammer 40,000: Rulebook (4th Edition), pg. 139
- Warhammer 40,000: Rulebook (3rd Edition), "Other Dangerous Aliens (Sketch)," pg. 116
- White Dwarf 99 (UK), Advertisement - Ambull Model, pg. 48
- Liber Xenologis: Observations from a Blackstone Fortress (Sourcebook) by Darius Hinks, pg. 116
- Caves of Ice (Novel) by Sandy Mitchell, Chs. 5, 6, 16