Vampiri are like the mortal version of vampires, also called Dhampir in some regions. The Vampiri are true vampire-human half breeds, the result of a fully fed and thus sexually functional vampire mating with a human. There are two kinds, the first is where a human mother is impregnated with the seed from a male vampire, this is by far the most common as the male vampire only need be fully fed for a short period of time to complete the deed. Secondly is there a female vampire is impregnated by a male human, this is far more rare because of the fact that the female vampire requires a steady supply of blood to keep their body alive and active during the entire gestation period.
Human Mothers
When a human gives birth to a vampiri, at the end of is gestational period (roughly 9 months though not always), it will claw and bite its way out of its mother which nearly always results in death. There are lore which states that the fetus can be cut out of the mother early and save both child and mother, but this has yet to be confirmed. In all cases the child is born hungry and will kill and feed from its mother upon birth.
Vampire Mothers
The child is born normally to the mother due to the extended durability of the vampire body. The child is unable to free itself with claws and teeth from the mother's body and thus must be pushed out, as with its counterpart the child is born hungry and will immediately seek sustenance like a feral and rabid animal.
Differences from Vampires
Unlike vampires, the vampiri do not have retractable fangs. They are born with canine eyeteeth that fall out within a couple days of birth. Their canines, when they grow in, are longer and sharper, more pronounced than those of humans, but still are not sharp enough to tear skin without making a mess. Most vampiri file their canines to a sharper edge and use them in combination with razors or knives to feed. Nor do they possess that mysterious gift that grants vampire victims pleasure and passiveness in the feeding process.
Yet another difference is in the way vampiri procreate. They can not embrace or be embraced. They must be born, and if one attempts to embrace a vampiri into their clan, the vampiri will simply die as the two bloods battle each other. Vampires generally despise the 'mongrels' but will not combat them unless strongly provoked, though they are not protected from the hunters.
Vampiri, most of the time, have enough of the genetic traits of a human to look perfectly human except for their longer and sharper canines. This is not always the case, other aspects of the vampire can be passed along, such as exceptionally pale skin, dead-looking coloring, and other qualities of the natural undead look and state of a full vampire who has not fed. In these cases, the qualities do not go away when the vampiri has fed, unlike a vampire that can return itself to the healthy state the body knew when it was human. Much like the demonic cousins the Broxa, the level of humanity present both personality-wise and physically is determined by the amount of vampire vs human in the makeup of the vampire. Usually for pregnancy to occur they must be in some sort of balance, but not always.
Abilities / Powers
The unnatural nature of the vampire passes down to the child in the form of some affinity with magical or psionic energy. In rare cases, the child can inherit an affinity for both especially in cases where the mother and father are both somehow gifted. A gifted human, however, would be much harder for a vampire to impregnate / be impregnated by due to unknown but powerful natural forces and instincts.
Peculiarities
A vampiri often has some kind of a strong appetite for some form of vice. Usually, it is sexual in nature, some kink or strong sexual desire which is compulsive in nature. As with most things involving humans, a lot depends on the environment of the person and how they grow up. Almost always, the attraction to some vice is compulsory to such an extreme that they feel the must fulfill that need only second to the desire for blood and to continue being alive and youthful.
Interaction with VX
Since a vampire is the result of an infection with the VX Virus one can think of the vampiri as a creature which is at the same time immune and a carrier to VX, though due to the unique nature of the VX Virus, it is a mutated variation that cannot spread beyond the host it is born into.