The Dark Angels are a Chapter of Space Marines in Warhammer 40,000. They were the first legion of Space Marines. Their homeworld was Caliban, where their Primarch, Lion El'Jonson, grew up. However, half their number rebelled following the Horus Heresy, and they ruthlessly hunt these "Fallen Angels" while keeping the Fallen's existence secret.They feature in the novel Angels of Darkness, the The Legacy of Caliban trilogy, and the Space Marine Battles novel The Purging of Kadillus, all by Gavin Thorpe. They also feature in the Horus Heresy novels Descent of Angels and Fallen Angels.Not to be confused with Dark Angel.Also check out the Character sheet.
Better to Die than Be Killed: With a doomsday virus having been tampered with, and unwilling to sacrifice the planet to escape their base, the squad in Angels of Darkness decide that it would be better to kill themselves than show weakness when their power armor fails to sustain their lives.
Career-Ending Injury: In Master of Sanctity Telemenus suffers a daemonic plague infection, forcing the Apothecaries to cut his right arm and everything below his waist to remove the infection. Telemenus later realizes that his fighting days are over.
Death World: Caliban was not a nice place before it blew up. Mostly due to warp taint and the vicious beasts that resulted from it (at least until the Lion led a crusade to kill them all). These days, the Dark Angels get their recruits from a number of Death Worlds, such as Piscina V, which is deliberately left untouched by the Imperium so the Dark Angels can recruit its inhabitants.
Heroic Blue Screen of Death: In Angels of Darkness Boreas has such a massive one following his learning that the Chapter never told him about the annihilus, proving that Astelan's claims of Lion El'Jonson's mistrust of the Dark Angels was right, that he nearly kills himself.
Ignored Epiphany: After nearly destroying Piscina IV over his obsession with the Fallen in Angels of Darkness, Boreas realizes that the Dark Angels have lost their way, and makes a recording of an impassioned speech begging the Dark Angels to stop being so obsessive over the Fallen. When the Dark Angels arrive to investigate his death in Ravenwing, Sammael considers Boreas a heretic for failing to pursue the Fallen.
Interservice Rivalry: In Ravenwing the Fifth Company begin developing a rivalry the Ravenwing over deployment, with the Fifth Company feeling that the Ravenwing get the more glorious deployment with the Fifth being placed in a support role. Sammael does have a good reason for deploying the Ravenwing, specifically to hunt for renegade Space Marines, but he can't tell the Fifth that.
The Reveal: In Angels of Darkness The Fallen on Piscina IV were after the gene-seed being stored in the Dark Angels basilica, which Nestor was guarding. And they tampered with a virus installed as a fail-safe after the Ork invasion. All of which was kept secret from Boreas.
Sinister Minister: Interrogator Asmodai, who firmly believes The Ends Justify The Means. It's believed he doesn't care about "saving the souls of the Fallen" anymore, just collecting more black pearls. It is hinted that Asmodai has gone off the deep end and is simply a sadist who enjoys inflicting pain; notably, despite his long service, he only has two black pearls for redeeming Fallen - the greatest of Interrogator-Chaplains had 13. Master of Sanctity final has some Asmodai's point of view: he legitimately believes that the Fallen need to be stopped, as his first encounter with the Fallen saw one wipe out an entire planet (Never mind that Asmodai himself considers destroying a planet an acceptable price for stopping the Fallen). At the same time, Master of Sanctity also reveals that Asmodai's first encounter with the Fallen did drive him insane, and he's fully aware of it.
Treachery Cover Up: Following the rebellion, the Dark Angels have hidden all information regarding the destruction of Caliban and the Fallen's existence. This includes up to and including killing Inquisitors who investigate Caliban's destruction. In Ravenwing it's revealed that the Inner Circle keep a lot of the truth about the Horus Heresy from the rank and file battle-brothers, such as it's existence.
Wham Episode: In Pandorax, Kaldor Draigo lets Azreal know the Grey Knights know about the Fallen, and have known for quite some time. It gets better from there: one of the eight founding Grey Knights was a Dark Angel, and at some point had "switched fates" with Cypher, in turn implying Cypher is a powerful psyker!
Would Hurt a Child: When one of the potential Aspirants balks at the prospect of Nestor opening him up, Boreas takes him aside and explains that if he refused, his family would be shamed. The kid realizes he has to do this, but Boreas says there are no second chances, and calmly snaps the kids neck, leaving him in a room filled with decayed bones, implying that the Dark Angels have been doing this for as long as they've been recruiting from Piscina V.