Deliverance
Deliverance is a touching 1970s-era love story starring Ned Beatty in scenic northern Georgia (the US state), often mined for ideas for instance by the something*positive webcomic, Knights of the Dinner Table #3, and the ogres in early Pathfinder. Do feel free to watch this family-friendly movie with your special someone.
In the Warhammer 40k line it's Corvus Corax's home moon, known as Lycaeus before he liberated it from the Tech-Guilds.
History
Great Crusade
Before the arrival of our favorite raven, Forge World Kiavahr's moon was was known as Lycaeus. Kiavahr, despite being a Forge World, was not ruled by the Mechanicum, instead being ruled by powerful Tech-Guilds. In those days, the Tech-Guilds would send "the worst criminals" (people who could not meet production quotas) to Lycaeus to mine the moon's valuable minerals.
Tech-Guild overseers ruled over the moon, but that was soon to change. Sometime after 800.M30, a pale boy landed on Lycaeus, and was named Corvus Corax ("the Deliverer" in the local Low Gothic dialect,) and upon seeing that the moon's population were entirely Kiavahran slaves, decided to liberate them. He led a slave revolt, defeating the Tech-Guild forces on Lycaeus, and renaming the moon Deliverance. Without the ores from Deliverance, Kiavahr's economy broke down, and the Tech-Guilds went to war with each other. Corax only joined the Imperium when the Emperor agreed to bring peace to his people, which he did by having the Mechanicum take over Kiavahr. This turned out to be only a band-aid on the problem, as the Kiavahran guilds and the Mechanicum barely got along, and people from Deliverance were still treated as second-class citizens. Things deteriorated badly enough that some of Corax's old freedom-fighter buddies turned back to terrorism to express their displeasure, which upset Corax no end when he found out. He executed one of his friends for his actions, then pledged to return to Kiavahr when the Great Crusade was over and set everything to rights. The Horus Heresy obviously threw a massive wrench into this place, and by the time Corax got home he had other issues on his mind. It's unknown whether Corax did anything about these problems before he disappeared into the Eye of Terror, but considering Kiavahr and Deliverance are still a part of the Imperium ten millennia later, things apparently worked out okay.
Now
The Raven Guard maintain relationships with the people of Deliverance, making their people intensely loyal. Deliverance and Kiavahr produce lots of ordnance and ammunition, which should be useful when Hive Fleet Kraken arrives.