Half-Elf
A half-elf is a hybrid of an elf and a human. Despite the elven taboo against it, they show up every so often. The circumstances that result in half-elves with human mothers are more common than the circumstances that result in half-elves with elven mothers, but this has more to do with the planes than the genders.
Basic Information
Anatomy
Half-elves lack horns, and by extension lack the elven ability to shapeshift from a young age.
A half-elf is distinguishable from a human by the traits they inherit from the form their elven parent settled on before having them. Family resemblance to both parents means that the less human their elven parent looks, the less human the half-elf will look. In the event that their elven parent didn't settle on a permanent form before having them, half-elves appear human aside from having pointed ears.
Genetics and Reproduction
Half-elves are essentially human by elf standards and essentially elves by human standards. Thus, further generations are still "half-elves" even as the true fraction shrinks. Humans consider the elven heritage moot after about three generations (meaning an elven great-grandparent is the furthest back that a "half-elf" can inherit from). Elves, though, cannot discount any amount of human heritage, because it prevents horns from developing, and hornless elves can't shapeshift.
Like humans, female half-elves don't need to be in on a specific plane to have children on the normal timescale. They are, however, about half as likely to get pregnant in any given situation as a human would be.
Growth Rate & Stages
Half-elves mature into adulthood as humans do, but "stick" in every stage of adulthood for about five times as long. This gives them a lifespan of nearly three centuries, but those centuries aren't quite spent in perpetual youth.
In contrast to elves, the plane that half-elves are on has no impact on their development. The fae aspects of their biology don't age at the "normal" rate in Emain because their human half brings enough "Droswal" along for the ride to keep them just as "slowed down" as usual. (Meanwhile, humans already age the same way in Emain and Droswal.)
Additional Information
Uses, Products & Exploitation
Like all humanoids, half-elves can be used as a source of spirit filaments. This is illegal.
Geographic Origin and Distribution
Half-elves are uncommon, but may live anywhere that humans and/or elves do.
Perception and Sensory Capabilities
Half-elves have the better low-light vision of their elven parents, but their senses in general aren't as much sharper than humans' as elves' senses are.
Most half-elves can understand the magical signals used in the Sylvan language, but it takes them time to learn rather than being automatic and innate like it is for fae. Half-elves mostly compare the signals to colors and scents, which full fae insist is not an accurate description.
Civilization and Culture
Interspecies Relations and Assumptions
While elves are generally tolerant of the existance of an individual half-elf that they get to know, elven society is broadly wary of half-elves. The Sylvan Courts in particular tend to be difficult for half-elves to interact cordially with, entirely due to the Courts' end of the deal. While one might expect elves to call half-elves "half-humans" instead, this isn't the case. By missing out on the childhood experiences of shapeshifting, ruder elves will say that half-elves are half as well-rounded as they ought to be.
Humans tend to have no real compunctions about half-elves, in terms of production or interaction. It's not atypical for humans to be weirded out by half-elves, typically because of their proximity to elves and because of elves' proximity to fae, but that attitude comes more often from a place of ignorance than from a place of malice.
Other races naturally regard half-elves with a mix of the reputations of humans and elves.
