Blood Drinkers
One of the successor chapters of the Blood Angels from the Second Founding, the Blood Drinkers are a proud chapter that conceal a dark secret that may yet damn them.
Like all their parent and sibling chapters, the Blood Drinkers suffer from the twin curses of the Red Thirst and the Black Rage. But unlike their fellow Blood Angels successor chapters, they have learned to embrace the thirst and make it part of their way of life and traditions. Literally, they have gone full vampiric, and like vampires drink lots of blood to control their cravings.
Few, if any, are aware of the feasts where the chapter's marines gather to drink vast amounts of blood to sate their thirst, and the Blood Drinkers go to great lengths to keep their shame secret. Operating out of planet San Guisaga (OK now GeeDubs isn't even trying), they fight to master their corrupt flesh and to prove themselves the equal to their brothers in battle.
At first, the Blood Drinkers were hit harder by the Black Rage than any other Blood Angels successor, but was saved after a battle-brother by the name of Holos was instructed in a dream to climb to the top of a mountain where he supposedly met an angel who promised to teach him a blood-drinking ritual that would stabilize the Black Rage. Unknown to the rest of the Chapter, this "angel" was actually Kairos Fateweaver, and the ritual came with quite a few strings attached.
Because of this, Black Raging Blood Drinkers have about a 1% chance to relive Captain Holos' big climb up the mountain instead of Sanguinius' battle with Horus. At the end of the climb they meet The Fateweaver. Mr. Weaver gives Holos instructions on how to do the blood feast ritual stuff mentioned above, and then he "tempts" the Black Raging marine with a choice: accept Tzeentch's blessings and damn the Blood Drinkers for eternity, or just re-engage their Black Rage and rot away in the Death Company as the rest of the chapter continues with their heretical rituals. None have accepted his offer yet, but Tzeentch isn't in any hurry.
Geez, and people give the Dark Angels shit about being closet heretics.