The Succubus (pl. succubi) is a supernatural humanoid creature that only exists in the Tartarus dimension. They could be summoned with madō to perform tasks by the summoner. However, they do not form contracts, allowing them to disobey or not completely do as ordered by the summoner. However, they usually do as they are told for amusement. They have the capacity to shapeshift, even to imitate the appearance of another individual, allowing them to hide from the general populace.
Succubi are characterized by their red-tinted skin, humanoid appearance, and demonic attributes such as pointed tails and bat wings. Alongside these, succubus hands and feet are clawed and are capable of ripping hard surfaces that many other species cannot damage without aid. Succubi are exclusively female and most peoples consider them to be attractive in appearance. They have the power to shapeshift, allowing them to hide their appearance from others or disguise themselves as another individual. However, this metamorphosis is limited to the exterior appearance: a succubus is incapable of imitating organ systems and functions of other species, such as the aquatic respiratory system of the syrens.
The entire species can be classified as weavers, though they do not contribute to the population of weavers on Earth due to living in a separate dimension. They only appear on Earth if summoned by a weaver.
The saliva of a succubi appear to have a high concentration of chemicals designed to seduce others. Despite succubi being only female, they are capable of using the properties within their saliva to seduce females of other species, suggesting that the chemicals target and stimulate the brain to produce sex hormones within a target individual. It is worth noting that succubi are believed to be bisexual.
Succubi are capable of crossbreeding with other humanoid species through sexual intercourse, though they are incapable of producing male offspring. The introduction of the male chromosome to a succubus offspring usually leads to a miscarriage during pregnancy, for an unknown reason. Since succubi have a low capacity to reproduce, they intermingle with other succubi by using an unknown madō-based procedure to fertilize an egg. The process is often referred to as "spreading blood" by succubi.
It is unknown whether succubi are capable of dying of natural causes, since they have the capacity to quickly regenerate wounds and they do not appear to age, holding a youthful appearance for extraordinarily long periods of time. However, they have been known to die from wounds sustained from combat, especially wounds inflicted with madō.
The female offspring of a succubus possess the same physical characteristics as her mother, though at a lesser extent due to the dilution of blood. Half-succubi cannot shape shift, manipulate madō, or possess the seduction chemical found in succubus saliva. Their physicality partially depends on the species of the father, creating greater variations of appearance than succubi themselves, though they typically only have the biological structure of the mother succubus. Most half-succubi retain the mother's good looks, though this trait can be diluted through further interbreeding. Despite succubus half-breeds being exclusively female, the offspring of half-succubi could be male, though the likelihood is low.
The succubi have a very loose hierarchy, consisting only of a leader called the Queen, currently a position held by Lilith. The succubi do not bicker with each other frequently, but arguments that do arise tend to be resolved on their own, without the need of intervention. The Queen only exists to maintain a sense of leadership in the case that problems that may threaten Tartarus arise, which remain to be extremely rare occurrences. The Queen almost never answers the summons of a weaver.
It remains unknown whether the succubi have their own language, though many researchers believe that they do. Succubi are capable of speaking the common tongue fluently, even imitating different regional accents with very few flaws.
Succubi refuse to sign contracts with weavers, causing one to frequently have a degree of distrust towards a succubus' words and actions. They typically do as the summoner weaver orders, however, for the sake of self-amusement.