Left Hand

D is the host for a sentient symbiote, Left Hand, a wisecracking homunculus with a human face residing in his left palm, who can suck in massive amounts of matter through a wind void or vacuum tunnel. Left Hand enjoys needling the poker-faced D, but only appears as needed, rarely witnessed or heard by anyone other than D, yet aware of many of D's thoughts and actions. At all other times, D's left hand appears normal. Besides providing a contrast to D's reserved demeanor, Left Hand is incredibly useful, possessing many mysterious powers such as psychometry, inducing sleep, hypnotizing others, determining the medical condition of a victim, absorbing matter, energy, and even souls and magic, healing and reviving D and himself, and the ability to size up the supernatural powers or prowess of an enemy, even beyond D's keen senses. After absorbing four elements, Left Hand can use them to generate powerful attacks, regenerate D and himself, and to transform D into full vampire state rivaling Sacred Ancestor. Left Hand can store absorbed objects in a pocket dimension inside his stomach, and later spit them out. In the first and second novels, Left Hand can also revive D when his physical condition is suffering, by consuming the four elements and converting the resulting energy into life force. This ability even saved D from the usually fatal for vampires stake through the heart he received from Rei-Ginsei in the first novel. Left Hand has its own mind and will, and acts as D's guide and sole permanent companion, providing a reservoir of knowledge pertaining to the lost Noble culture. So far, Left Hand's origins are unknown, and it is unclear how they came to be joined. However, some of its nature is revealed in the third book, which features a similar creature; it is implied he was one of the Barbarois (mutant/demon hybrids) who served in the personal retinue of the Sacred Ancestor, and was experimented on by him to increase his powers over other Barbarois.