All Sons of Sanguinius are defined by the Red Thirst and Black Rage, and how they react to them. Those gripped by their mild forms are terrifying melee combatants, ripping limb from limb and battering their foes into submission. They are exceeded only by the pure fury of those marines who have lost themselves to the twin curses of Sanguinius's bloodline. Each chapter has their own traditions and tools for staving off the curses, but they are unified in their preference for and specialty in close quarters combat.

Or at least, they are nearly unified. The Sanguine Sentries take a different approach. In order to stave off the Red Thirst and the Black Rage, they avoid melee combat and use of the omophagea, killing from a distance to keep the horrific instincts which drive them to eat and drink their foes dormant. In this manner, they stay untouched by the Thirst for much longer than their cousins and progenitors. However, when they do succumb, they fall much faster and harder than those chapters whose order of battle lets their marines sip lightly from the cursed cup. Accordingly, they do not put all those who have fallen into a Death Company, but divide them into two special divisions.

On the first occasion where a Sanguine Sentry breaks ranks to charge into melee, if he survives the battle, he is inducted into the Beast Company, whose livery is brown with red markings. The Beast Company are those who have lost the discipline the Sentries prize, and can no longer be held back from charging into close quarters with the enemy. They are not kept drugged or restrained, but live apart, and are never trusted again by their brothers.

The Death Company, which wear black armor with red markings as in other Blood Angels descendants, are those who can no longer restrain their bloodlust to enemies or who have been irrecoverably lost to the Black Rage. These are kept imprisoned under sedation, like in other chapters. Despite their knowledge that if they do not first die honorably, the Death Company are a glimpse of their future, the Sentries look on them with pity and disgust.

This disgust extends to their cousin chapters, and even the Blood Angels themselves; the Sentries consider their enthusiasm for close quarters a foolish waste which condemns them and their brothers to the curse needlessly quickly. They do make exceptions for the Lamenters and Angels Resplendent, who remained untouched by the Thirst for centuries and so receive the Sentries' respect. Despite their disgust, they maintain a sense of filial duty toward the Blood Angels, and answered the call to defend Baal against the vile Tyranids. This was the first they encountered the renamed Angels Penitent, and 1st Company Captain Tharella, leader of the Sentries on Baal, nearly came to blows with Reclusiarch Relian when he discovered the mockery the Sentries' favored cousins had made of themselves. Tharella stated his intention to report them to the Inquisition, but he was nearly killed and entombed in a Dreadnought after the defense of Baal, so it is unknown whether he managed to make good on this threat, directly or by proxy.

Colors: Unpainted steel with brown accents, the hue of dried blood. The Beast Company spreads this brown to their whole armor and repaints the accents red; the Death Company replaces the brown with black as normal.

Heraldry: A silver chalice, inverted, on a red field