As the name implies, half-elves are the offspring of the unlikely pairing between elves and other. Many races, specially humans, find themselves attracted to the delicate beauty of the elves, they desire to possess them physically at any cost. Thus many half-elf children are born to elven mothers, taken against their will by some mercenary or captured by a rogue lord of a faraway land. The times the child is born of loving parents is rare if not unique.
It may seem strange to the reader that the half-elves are their own race, after all other races join together with more frequency than elves. The simple truth is that the word half-elf is not merely an appellation but a judgment. Elves of whatever breed are proud of their heritage and, as a rule, do not willingly join with others not their kind. They therefore look upon the half-elf with a mixture of disdain and disgust. To them the half-elf is at best a pitiful, inferior creature and at worse a mistake that should have never been born. In fact the word "karith" or half-breed is a curse in all elven tongues.
Though looked down upon, this mixing has lead to a hardy race. The human-elf mix is a commendable one, incorporating the agility of the elf and the solid strength of a human, though admittedly diluted in its degree. They retain their elven vulnerability to iron however, as well as their excellent night vision and resistance to mind spells. The mixing has also produced an unforeseen side-effect, that of making them incredibly resistant to poisons.