The Abyss is an otherworldly realm of shadows that is known mainly as the source for the manifestations of Obtenebration, the signature Discipline of Clan Lasombra. To many Lasombra neonates, the Abyss is little more than a metaphorical conceptualization of their mastery of darkness, but experience quickly teaches them of the undeniable reality of the Abyss as a literal place, an endless void of eternal night. The chill darkness of the realm extends beyond the visual and physical and into the spiritual; long-term habitation of the Abyss is dangerous even to the Cainite psyche. Nevertheless, elder Lasombra occasionally use the Abyss as a neutral meeting place, outside the scope of their enemies' and rivals' prying eyes. In particular, the most secretive meetings of the Friends of the Night are sometimes called into session here.
Some Lasombra practice Abyss Mysticism, the quasi-theological study of the Abyss and of its manifestations via Obtenebration. In the Dark Ages, Abyss Mysticism doubled as a system of rituals that synthesized Obtenebration with the trappings of blood magic; these rituals have apparently fallen into obscurity in the modern nights. Nevertheless, the study of Shadow Occultism (a variant of the Occult Ability that specializes in the use of Obtenebration) is still practiced among the clan's mystical scholars, theologians, blood sorcerers, shadow-walkers, and other devotees of the mysteries of the Abyss. One reclusive faction of the Lasombra, known informally as the Abyss's Children, is singularly devoted to the study of Obtenebration and the Abyss.
Although the Abyss is seemingly empty of native inhabitants, the realm itself is quasi-sentient, and will sometimes display physical or mental manifestations. Such manifestations can be summoned into the material world by high-level mastery of both Obtenebration and Shadow Occultism, though these conjurations are not without risk. One especially powerful Abyssal creature was summoned by Cardinal Ambrosio Luis Monçada, only to turn on its master and precipitate his final death when the Cardinal was distracted by his childe Lucita and her ally Fatima. An even more noteworthy Abyssal inhabitant is the disembodied spirit of the Lasombra Antediluvian himself, which was separated from his body and integrated into the Abyss itself when his physical body was apparently slain by his childe Gratiano. Since this event, it is unclear to what extent, if any, the will of the Abyss's semi-sentient manifestations can be separated from the will of the undying Antediluvian.