A Necrobus was a member of an ancient race of nocturnal creatures which sustained themselves by feeding on the sexual energies of human beings. Due to the celibate nature of the curse, those who bore the Darkness were regarded as the natural enemies of the Necrobi and vice versa.
Due to their similar namesake as well as their dependency on sexual predation, the necrobi were closely parallel with the demonic succubi. Despite their similarities, the necrobi were not demon in nature and it is unknown if the two breeds were numerous enough to have encounters.
Despite their relative longevity and endurance even in their weakest times as they were starved of their energies and their ranks were diminished to endangerment, the necrobi would meet their end at the hands of Witchblade bearer Sara Pezzini and Darkness wielder Jackie Estacado.
Their precise origin as a species was never revealed. What little was revealed of their history describes them as once ruling over all of humanity as an imperial legion under the dominion of the Heart Necrobi, a council of androgynous elders caught in a perpetual orgasmic frenzy.
The necrobi appeared human for the most part. Specific members of the species such as Cull or nest guardians appeared noticeably larger and more muscular than most men. All necrobi exhibited a degree of preternatural strength and durability; amplified by the consumption of souls.
The necrobi were shown to harvest souls from their partners while still alive; preserving their bodies in a blue crystalline chrysalis. This was considered a gift on the part of the necrobi. This made the necrobi custodians of their souls; should they die, their victim would die.
The necrobi possessed their own spoken and written language and it was considered an honor to speak it in the presence of the Heart during formal occasions. However, the council was noticeably partial to modern English due to their mastery of 20th Century North American dialects.