Children of a Lesser Hell-God

Contrary to what many assume, vampires come in a variety of different types and bloodlines.  More, creatures exist that blur the line between Living and Undead.  Most famous of these is the dhampir--offspring of a human being and a vampire.

Stranger still is a someone who, although bitten, does not transform into a full vampire.  Exactly why remains unclear. There seem to be some people who (for some reason) resist the complete change.  Certain very powerful vampires seem capable of deliberately creating this bizarre hybrids.  One expert, whose exploits regarding such ended up as a film titled Zoltan, Hound of Dracula, coined an accurate term for them.  Pseudo-nosferatu.  Others call them ghouls.  Another source refers to them as carouche.  Yet they may perhaps be best known via the most famous such entity.

Renfield.

The name conjures up a specific image.  A madman in padded cell.  Bound in a straightjacket.  Hoarding flies, then spiders--intending to eat them.  Not entirely accurate, however.  When one looks for similar beings in the history of vampires, one needn't go far to find them.  Keep in mind also that it remains unlikely all the individuals identified with the name actually bore it.  Accounts of Dracula's soul-clones often end up tweaked to resemble Stoker's novel.  The motion picture Nosferatu included a person who ran a business, was in fact a respected man of property.  Yet who went mad, obsessed with devouring tiny lives, and utterly devoted to serving one of the living dead.

In the motion pictures Fright Night and its sequel, Jerry Dandridge and his sister each had a servant--formidable men in their own right.  They each ate bugs.  When killed, they dissolved into a mass of the creatures, leaving a putrid skeleton behind!

From these and other clues we may well deduce facts about this odd supernatural creature, neither one thing nor the other.  Consider also how the Count of Saint Germain has such a servant, well-treated, even a friend.  Yet dependent upon the vampire.

1.  All pseudo-nosferatu are created by vampires.  Exactly how remains a mystery, but it needn't be permanent.  Xander Harris began the process but returned to normalcy.  The Renfield of the novel even rebelled against his Master (I myself believe the soul-clone Dracula-Mordante was in England before Dracula Prime, and it was he who transformed the man known as Renfield).
2.  Pseudo-nosferatu evidently need to remain in the proximity of at least one vampire.  One almost never hears of one by themselves--and when they are, their efforts to bring a vampire near them are ceaseless.
3.  The pseudo-nosferatu has a will that has been enthralled to that of another.  Indeed, they behave much as a drug addict would if their opiate-of-choice could walk around, think, act on its own agenda.
4.  One of the distinguishing characteristics of the pseudo-nosferatu is that they feed on "lesser" lives.  Animals or insects usually.
5.  Lacking nearly all the weaknesses of a true vampire, a pseudo-nosferatu possesses but one power in common with the true undead.  They are stronger than a normal human being.  They may or may not gain extended youth and vigor.  But they remain harder to physically subdue and kill than is usual.