The Dark Angels were the first legion of Space Marines to be selected by the Emperor, the first to undergo the implants and surgeries required to become a Space Marine. Since their founding, have fought valiantly for the Imperium. They served in the Crusades, helping to unite mankind and eliminate aliens. During the Horus Heresy, they were held back from the fighting by Horus. Their legions, however, were split in the Great Betrayal - the garrison left to defend their home planet turned to Chaos. When the Dark Angels returned home, they were fired upon and in the ensuing battle, their homeworld was entirely destroyed. This secret shame haunts the Dark Angels to this day as they serve the Imperium with unflinching loyalty.