Crillon is a world in the Astoth sub sector given the designation of a civilised world. Boasting a population of 22,000,000, it is a developing world that is perfectly self-sufficient in terms of food-supply. Crillon has no specific purpose to fulfill, and is being allowed to develop naturally.
To the Tempest Angels nearby, they have proven strangely protective over the planet; engaging any foe with furious zeal. Most say that is simply the Chapter fulfilling their oath to safeguard the sub-sector, but the truth is that to the Tempest Angels this planet is a reminder of an age where humanity reached out to the stars and colonized planets to fulfill humanity's pioneering destiny; of an age where the Emperor himself lead a Great Crusade to find these planets and bring them back to the arms of the Imperium. A planet of hope in what the future may bring.
Despite having a nearby Space Marine Chapter, Crillon fields its own Planetary Defence Force- mostly with weaponry provided by the surrounding planets in the sub-sector.