For all you fluffy bunnies out there, here is the story behind Dark Vengeance and a bit of insight into the characters within the two forces.

To start of there is a novel in the set is based on by C Z Dunn and is in limited supply on Black Library so go and check that out if it interests you.

So, first off the Dark Angels. At the core they are the 5th Company led by newly appointed Company Master Balthasar formally of the Deathwing. Also accompanied by members of the 1st Company, the Deathwing, members of the 2nd Company, the Ravenwing, and a librarian by the name of Turmiel.

The task force is out for revenge for the predecessor of Balthasar, Company Master Zadakiel at the hands of the Crimson Slaughter's Helbrute. Hence the name of the box set Dark Vengeance.

The Crimson Slaughter, formerly the Crimson Sabres Chapter but were declared renegade in M41 following signs of psychological  instability and over zealous prosecution of their campaigns. Led by former Chapter Master Sevastus Kranon now Kranon the Relentless. They are accompanied by a fearsome Helbrute, Mortis Metalikus, who was once Sevarion Kranon, actual brother of Sevastus. After refusing to give in to the blood frenzy that claimed his chapter he was imprisoned by his brother and driven mad before finally being entombed within the metal sarcophagus of a Helbrute.

The Crimson Slaughter are on the planet, Bane's Landing, seeking The Hellfire Stone, which once anointed with the blood of a Space Marine will open a gateway to the warp and allow a powerful deamon of Khorne to enter from. However it appears that Kranon the Relentless seeks it to release his chapter from their bloodthirsty curse and silence the voices in his head once and for all.