"A Blood Dragon should strive for excellence in all matters, but especially in the martial pursuits. Countless Knights and Warriors have I bested in battle, and many more come in hopes of slaying me each year. Unlike them, the passage of the ages strengthen me. You can never know what it is to know what certainty that one's skill with blade and bow increases year upon year, instead of deteriorating into middle age, dotage, and eventually death. That in itself is reason enough to give up mortal life and take up the eternal challenge of immortality..."
- —Sir Holbein of Blood Keep, Blood Dragon Champion
A Blood Knight leading a horrific army of the Undead
The Blood Knights were once an honorable brotherhood of Imperial Knights that protected the lands just west of the Empire of Man province of Wissenland. However, after their horrific transformation into Vampires, these once noble Knights have since become the bearers of the unholy blood of the Blood Dragon bloodline. This transformation came about when an unexpected visitor demanded entrance into the confines of Blood Keep in the Imperial year of 1887 IC. This man held the name of Walach Harkon, a student of the Vampire Firstborn Abhorash himself. In one single night, Walach Harkon had personally dueled and slain every single member of the original Knights of the Blood Dragons, and turn those he deemed worthy into Vampires.
Corrupted by the influence of the Vampiric curse, these once noble Knights have been unwillingly turned into the monstrosities they swore themselves to hunt down and defeat in the name of the people and the villages under their lordship. Blood Keep became a Vampire lair, from which the deathly knights preyed upon those they once protected and loved.
Many decades later, the Witch Hunter Gunther of the Van Hal family had discovered the truth of their origins and attacked Blood Keep with an army sent from both Wissenland and Reikland, supported by no less than four Knightly Orders. The siege lasted for three years, and the bloodshed was like nothing the men of the Empire had seen. Van Hal and his soldiers destroyed many Vampires when they finally stormed the casde, and they hunted the survivors through the wilds for years to come. Afterwards, Blood Keep fell into ruin and its evil masters passed into myth. Though Blood Keep was brought low, many Blood Dragons escaped, scattering across the lands of the Empire, Bretonnia, Tilea and further afield. Fearsomely accomplished with lance and sword, these warriors became fearsome raiders, either mercenaries led by dark Kastellans or solitary duellists.
Since then, the Blood Knights are considered to be one of the most fearsome cavalry in all of the Old World. Their training and discipline in life is enhanced by the unnatural speed and strength of the vampiric curse. Blood Knights are nigh indestructible, riding with fangs bared through storms of arrow and shot. Such is their honour that they will refuse no martial challenge, and will fight at the forefront of an Undead army without question. It is said that even the fabled Grail Knights of Bretonnia cannot match the Blood Knights lance for lance upon the field. Though they retain the Dragon as their symbol, with blazons and crests in their likeness, their armour is encrusted with images of death and slaughter. Their blades are fell weapons inscribed with dark runes, chased with precious metals and fashioned in the likenesses of evil beasts. The knights do not ride fleshand-blood horses, but charge across the field upon evil Nightmares that are clad in thick barding painted with disturbing icons of necromantic power.
Source
- Warhammer Armies: Vampire Counts (8th Edition) -- pg. 45