A "degenerate universe": a comparatively tiny, partially formed, parasitic universe that is latched onto the Prime World (the universe as humans know it). This parasitic universe has few physical laws of its own and gets most of them from our universe.

The Parasite World occupies no physical space within the Prime World and can be accessed from anywhere by essentially falling into a lower energy state than what the Prime World's laws can support. Portals that produce this effect release energy when transporting objects/people from the Prime World to the Parasite World, but reversing the process requires significant energy input. This makes it very difficult to leave the Parasite World once you get there.

The vast majority of flora and fauna in the Parasite World are succubal or incubal; that is, they feed on sexual fluids and the potent magics they contain. Most beings that feed any other way are either Prime natives or descendants of Prime natives.

Sapients in the Parasite World tend to suffer from the “Vampire’s Dilemma”. They feed on sexual fluids, the magic within being far more energy efficient than standard foods that humans would eat. However, actually getting access to that food source is magnitudes less efficient than going out and hunting and killing an animal or grazing. Parasite sapients thus have great physical and magical abilities, but have to use nearly all of those abilities just to secure their next meal. This leaves little effort left to devote to things such as technological development, so succubus sapients are universally much more primitive than humans and advance far more slowly. In some cases, advancement has stalled entirely.

A species of bee-like sapients native to jungles in the Parasite World. Hydromels are succubi specialized in seducing and feeding on males of other species. As such, both of their sexes look, sound, and feel female by virtually any human measure. They are powerful swimmers and can hold their breath for extended periods of time, thanks to being descended from aquabees, an Order of various species of amphibious bee-like succubi.

Though hydromels primarily gain sustenance from semen, they can also drink (and in fact require) water as well, and are capable of eating ordinary food. Food cannot sustain them forever, but eating it does allow them to go longer between required feedings.

The more conventionally feminine of the two hydromel sexes, by human standards. Female hydromels tend to be slightly smaller and weaker than males, but also possess greater stamina, roughly on par with that of a human.

Hydromel females reproduce via receptors on their abdomens, which receive semen secreted onto the abdomens of males. However, while the "vagina" of a female isn't used for sexual intercourse, it still plays a part in hydromel reproduction. The vagina leads to a feeding tube leading to the primary stomach, which digests semen, but it also connects to the hydromel's birth canal. This can complicate feeding during pregnancy, as ingesting semen with the primary stomach can be risky at some stages of hydromel pregnancy, and the primary stomach mostly shuts down late into pregnancies. This requires the female to feed from their secondary stomach (which is connected to the mouth) which isn't as efficient. Pregnant hydromels rely heavily on the nutrient-rich honey produced by males in order to stay healthy.

Female breasts perform exactly the function that one would expect, unlike the breasts of male hydromels. Female breastmilk is used to sustain young hydromels until they can digest solid food and eventually move on to succubal feeding. However, unlike in humans, lactation does not stop after the children have grown, nor does it start during or shortly after pregnancy. While female hydromels are not constantly lactating, they have the ability to trigger or stimulate themselves to lactate for most of their adult lives. Because hydromels are inefficient at processing nutrients from food - even as infants and children, when they are unable to engage in succubal feeding - hydromel milk is incredibly dense in nutrients to compensate. This makes it extremely nutritious to non-succubal species like humans as well, and it is a way for hydromels to ensure their prey survives even if they cannot find food to give them.

Hydromel females can also produce a pollen from the membrane of their tails, but it has a different effect compared to male pollen. Where male pollen is debilitating and essentially forces their prey to put everything their body has into feeding the hydromel hunting them, female pollen has more of a rejuvenating effect, acting as a mild anesthetic while also aiding in the absorption of nutrients when breathed in. Paradoxically, this effect can be dangerous to prey if applied in the wrong way in conjunction with male pollen and honey, causing prey to utterly exhaust themselves feeding the male, and then overexert while feeding the female, fooled into thinking they are less worn out than they truly are thanks to the female's pollen.