Like all those with Noble blood D is afflicted with the uncontrollable desire for blood. D can seemingly go for long periods with out drinking blood but at times it leaves him vulnerable for his desire to overwhelm him. It takes an extremely strong odor of blood later in the novels. He may have become more resistant. This desire may also be linked to his berserk like rage and ability to change into full vampire. Usually drinking his own blood to transform, when the desire over takes him he immediately starts to transform with out consuming his blood and will attack and kill ally or foe. The parasite seems to be able to stave off the attack long enough for a person to escape.
A Noble who appeared in the ninth millennium. Also known as "Gullit the Corrupter." He wrote five hundred volumes on how loathsome he found the act of drinking blood. He tried various means to break himself of the habit, but all attempts ended in failure, and he ultimately disavowed his theories. His writings were all subsequently cast on the fire. Gullit is mentioned in regard to how there are no Nobility who triumph over the urge to drink blood.