Alphos (Fortress World)

+++PLANETARY DATAFAX+++

Alphos: Alphos was a human-inhabited world that was conquered during the first expansion phase of the Crusade. It was subsequently turned in to part of the Iron Collar, the ring of Fortress World protecting the Well of Night.

Alphos was only lightly defended during the Battle of Hethgard, but still managed to gain the upper hand against the Tyranid splinter fleet sent there. Something about Alphos made it very hostile to the invading Xenoforms, and more Tyranids died to the environment than to the guns of men. The invaders eventually adapted, and from a crashed hive ship a Tyranid synapse creature directed the remaining Xenos against the increasingly weak human garrison. The synapse creature was eventually eliminated by Barotta's new breed of Aurum marines, greatly reducing the Tyranid threat on Alphos. 

The searing hot sulfurous atmosphere makes Alphos a hell-hole, requiring heavy protective garments and breathers if you want to go outside, but it's vast mineral fields are too rich to be left idle, so the workers toil now, as they always have, stripping away one layer of rock to expose the next. The Adeptus Mechanicus did some preliminary terraforming studies, but the results were not promising, and the project was ended. Instead, a large number of Squat abhumans were moved here, as they are better suited to Alphos' harsh environment.