Angels

A large portion of Rock Candy 's cast is represented by Angels, a unique side-evolution to humans which are born of the Dream God, Descent 's blood, and birthed collectively by Sora Yuuji, who is typically referred to as the first Angel in Yuujian lore. They represent the purpose of Yuuji 's existence, and are thus held in slightly higher regard than regular humans, especially ones with powerful and useful Evokes. They also function primarily off of Ichor instead of blood like humans.

Biology
Angel biology has few differences on the surface, but internally they are actually very different to humans. Externally their only notable features are their horns and tails, the tips of which both come in many varied shapes and colours, and their wings, which allow them to fly for a time. They also sport long fangs in place of a human's canine teeth which have the ability to inject venom into a victim, which has a differing effect for every angel.

Internally, Angels contain many biological differences that seem to be intended to make them a more resilient species. Their blood is instead replaced with Ichor, which besides being brightly coloured and slightly thicker, has many mythic properties, and is decidedly the source of the angels' magic Evokes. They also have a slightly higher average internal body temperature at 39 C, as well as a small gland on either side of their head which stores their venom, which is invisible from the outside.

Angels also have minor mental differences to average humans, and for this there is little to no explanation even within the Citadel, and is presumed to be a result of a human brain experiencing such different internal stimulus. For one, angels have a slightly more animalistic survival instinct to that of humans, which sees them often push higher thought away when needed. This makes them excellent natural survivors, but it's rarely been tested due to Yuuji's barrier meaning there's almost nowhere to let angels survive natural-style. Secondly, angels have a pathological enjoyment of warmth, up to a certain degree, which makes them very prone to being cuddly and enjoying close contact with other angels or humans. This is assumed to be the reason why the warmest parts of Yuuji are also the most expensive places to live, and assumed to be why angels tend to have a much more casual attitude to affection than the average human.

Although angel diets don't differ from humans in Yuuji, they are biologically fit to be natural predators and are assumed to be designed such that a diet befitting one would be sufficient. Angels that are underfed in meats tend to become very lethargic very quickly, which can become a medical concern if not handled. This manages to happen a lot in Yuuji due to the extreme expense of most meats, of which almost all that is available is fish.

History
Angels have a relatively short but storied history, starting with Dream God, Descent. The otherworld being desired to save the memories of their home world before it disappeared into the endless night, and thus requested many beings across many worlds to carry the Ichor. Descent was nothing but refused, however, until they found Sora Yuuji on Earth, who finally agreed on the condition that the Ichor not change her children beyond human recognition. This was no issue, as the Ichor thrived off of only mild modifications to it's host species, and Descent gave Sora instructions on how to use the crytallized Ichor they'd used to prove themselves real to birth the first angel.

Sora ended up having many children with many of her followers in an attempt to vary the genetic stream as early as possible. The long term intention was to make Yuuji diverse enough that it can sustain both humans and angels within it's land into eternity, or until the barrier is removed.

Angel Variants
Angels have been found to have biological relatives which have slightly different lifestyles and biology to one another. Although only one other species is known to exist on Earth, the infinitely contagious Ichor and the Dream God's extended efforts to produce angels in our world mean it's likely possible there are more angels in other parts of the universe.

Yuropan Angels
Yuropan Angels, or Alter-Angels as they're called by some Yuujians, are a variant species of angel which were created and fostered in the Aztec-Asian city of Yuropa. Their differences to angels resemble that of a succubus, their wings being lowered to around their waist and their fangs being much sharper. They are notably unable to fly, making their wings mostly vestigial, but in exchange they seem to have much more powerful and external Evokes.

Yuropan Angels were created by the mining site where Dream God, Descent left their first cluster of crystal Ichor having not been entirely cleaned out. The remaining Ichor, over many years, managed to find its way into the genetic stream of a town forming above the site, eventually causing unknown and unchecked angels to be born there.

Otherworld Angels
Otherworld Angels, or Origin Angels as they're sometimes referred to in Yuujian lore, are the name given to the original species of angel which lived in Dream God, Descent's world before it's equalization, referred to usually as The Otherworld. Although none have ever been seen, likely due to the fact that every specimen is long gone, Sora was given detailed descriptions of them to share with her children.

Otherworld Angels were said to have thin coats of dark fur, much larger wings, far more powerful venom, and much simpler Evokes. This final point is linked to the fact that Otherworld Angels were much simpler mentally than any human, despite their societal living style, they were unable to make proper use of more complicated abilities.

When questioned about why Descent and the Otherworld Angels had the same blood, Sora explained that supposedly all creatures of their world shared the Ichor, which also explains it's ability to modify any living thing's genetic stream.