Culvaris: Are a seemingly other-worldly creatures that originated in 'the nexus', and are unique in that they are never bound to any single form, in fact making them shape shifters, though their capabilities vary depending on the world they are in and they are restricted to shape changing to the 'smaller' variety of the native species, and in fact are 'forced by nature' to take a form of a native creature when entering another world [one of those above, or perhaps a human even], though they can tweak and alter this form in countless different ways. The only ever present quality of their body is that they ALWAYS have wings, a pair on their back and a smaller pair on their head, no matter their form, acting as the main identifiable quality of the Culvari Race, as well as the ability to use elemental magic to a degree regardless of the form they are in. Note: They can utilize 'any' elemental magic, but to a lesser degree of that possible of 'natives' who use that element, such as the Salumo, though a specific element 'is' somewhat stronger when in it's corresponding world.
Their main 'power' actually is their wings, while still enabling flight, they also are unnaturally durable like armor, and infact can be 'shifted' into various weapons, armor, clothing, or extra limbs. Because of the forced shift when changing worlds, they often don't worry about persistent clothing or weapons, and simply use themselves, magic, and whatever native weapon they can find.
They also have a unique form of 'mental' magic, though not in the sense of being able to read minds and brain-wash people, but more in the sense of creating shields to protect someone's mind from an out-side attack, or creating such out-side attacks, though often not fatal on their own, the diruption of one's cognitive functions can mean death by any number of other means.
They actually act as emissaries between the native creatures of each world when they can, as well as inspiring trade between worlds where possible, and are always identifiable from the natural lifeforms from their unique markings and wings. They are somewhat reveared by these creatures, not as gods or anything, that would be dumb, but more a race that is doing great work to foster relations between the creatures of different worlds
They are particularly unique in their 'food source' as they feed on the ambient emotional energy created by other species, though they can eat normal food when they want to, and can be affected by which form of emotion is most prominent, for instance, if they approach a settlement full of people who are suspicious and paranoid of other creatures, they may unwittingly become paranoid as well, likewise, if there is a lot of 'rage' in the air, they are more likely to feel anger. This goes along with their natural emotional vulnerability, they 'feel' more than other races, tough it is not completely un-controlleable, a Culvari is more likely to be driven into a fit of violent rage by being attacked than another species, as well they are more likely to seek vengeance of suffer greatly when a loved on is lost, and in such a fashion they also bond more strongly with their companions, easily becoming an unwavering ally.
A useful Note: When in the nexus, their shape shifting is unlimited aside from that they cannot take a form larger than they have the energy to produce.