Even when dealing with the Battle-Brothers of other Astartes Chapters, the Dark Angels often remain sullenly quiet at the Space Marine command councils and tactical briefngs, though that is not to suggest that they are any less effective on the battlefeld.When the Dark Angels do undertake joint operations alongside other Chapters, it is quite common for them to do so with others amongst the so-called "Unforgiven" -- the Successor Chapters of the original Dark Angels Legion.The Dark Angels stand first amongst the Space Marine Chapters, as they have done since their very inception as the I Legion.
Most references in the histories of the Imperium to its deeds during the accursed times of the Horus Heresy have actually been expunged.
Yet a legend persists that at one point the Dark Angels teetered on the very brink of heresy and that an act of the most terrible betrayal dishonoured all of the I Legion's feats of valour, leaving an enduring stain upon all of its Successor Chapters' honour.
There is no presumption that the leaders of the Dark Angels have any inherent superiority over those of the other Unforgiven Chapters.
Rather, the leaders work together closely, and if needed elect one of their number as nominal commander for the duration of the campaign.
When a Dark Angels force is committed to such a conﬂict, it invariably remains aloof.
Its offcers keep their own counsel on matters of tactics and strategy, and prefer to maintain their own lines of communication and supply sources.
Even though the Chapter has stood side by side with every major arm of the Imperium's military, it has always maintained a distance and aloofness that sets its brethren further apart from the bulk of Humanity, and even from other Space Marines.
When the Dark Angels join a larger force to execute a great war or crusade, they do so according to their own, unfathomable goals.
In one matter, however, the officers of the Dark Angels have superiority over those of the other Unforgiven Chapters, through the workings of the Inner Circle -- the Hunt for the Fallen.
When hunting those turncoat Dark Angels who escaped the Fall of Caliban, the Unforgiven operate under the auspices of the highest ranked of the Inner Circle, and the very highest of these is the Supreme Grand Master himself -- the Chapter Master of the Dark Angels.
The origins of the Dark Angels Chapter remain shrouded in mystery.