Herrick Thane, the leader of the Convocation in the Dark
A clan of vampire tweaks first encountered in Cableville in 8666 in the unlighted section known as the Dark. Several groups of near-baseline humans have established settlements in this region, including the Carodigians, a cadre of Mortalists who reject the use of life-extension technology. When the Convocation settled next to them the vampires began to infect the mortalists, converting their victims into effectively immortal vampires.
The Convocation claim to have existed for many millennia before arriving in the Dark, although there is scant evidence for the truth of this assertion. They retain no records of where or by whom they were created; it is possible that they are a relatively late modification of earlier vampire clades.
Like many other vampire clades they have biotech vasculoid circulatory systems, so that they do not need a heartbeat; they have augmented strength and sensuality, paler skin than the norm, and moderately augmented intelligence. The Convocation use a number of relatively hi-tech devices to conceal themselves, including small quantities of utility fog to change their appearance or to conceal themselves on occasion- they carry this u-fog in concentrated form in their elaborate and often outdated clothing.
They are unusual in that they can not reproduce sexually, despite having augmented sexual drives and desires; their genome is partially encrypted so that they can not be cloned without ultratech assistance. Not all of the information required for healthy growth and replication is included in their genome; the rest (the encryption key) is stored elsewhere, in the mind of the vampire emself.
When a Convocation vampire bites eir victim, a virus is introduced into the body which modifies the nuclear DNA of each cell to become like that of the vampires. The victim becomes resilient. sensual, and sensitive to many new stimuli. But the victim also becomes sterile, and subject to a degenerative genetic condition that can only be treated using additional genetic data stored in the memory of the vampire. This data is stored not as DNA, but as a string of digits in their physical memory, which is transferred into the victim during the process of 'making' them a vampire. The relevant memory storage systems of the vampire are biological, but are nevertheless augmented to reduce the chance of error to near zero.
If an attempt is made to clone the vampire this data will be erased, rendering the clone non-viable. With the additional data the vampire is effectively immortal. The only way that the Convocation can reproduce themselves is by biting other human-derived sophonts and infecting them with their biotech blood-replacement system. Most augmented human clades in the Current Era are sufficiently well protected against this sort of biotech invasion, so the vampires prefer to seek out victims with reduced resistance to such attacks, such as the Cardogians on Cableville.
Some of the more louche elements in the big cities of Spaghetti and elsewhere are quite happy to encourage a small population of vampires to prey upon themselves and their friends; a modosophont with fully active genetic defence systems is immune to a vampire's bite, unless they deliberately disable their defences, and even then they can usually cure themselves of the effects afterwards using moderately advanced gene therapy.
In recent centuries vampires of the Convocation clan have begun to appear on other worlds, especially those with long dark periods or low light levels. The Convocation might be seen as a threat by other denizens of the Dark and the other worlds where they are found, but they are not evil supernatural beings. They are instead an artificially created clade with an idiosyncratic lifestyle. Almost all of their 'victims' (who think of themselves as 'initiates') are quite happy with their new way of life.