Hatred is gained as much by good works as by evil.1
Orcs are intrinsically evil.
There are no “orcs” and “elves.” They are the same thing. They are polymorphs (no, not like that, wizard) of the same creature.
The switch is, somewhat inexplicably, the moral choices of the individual. At most basic, an elf is one which has consistently made good—altruistic, empathetic, righteous—choices in her life; an orc, one who has made wicked—selfish, callous, violent—choices in hers. The making of these choices moves the individual along a spectrum, one little bit at a time. The spectrum runs from the most ethereal elf to the most brutish orc, and while there are no hard stops along the way, every observer seems to exhibit a desire toward amateur taxonomy. Barring extraordinary event,2 each little choice—keeping the last bit of butter to oneself, lending a hand in another’s garden, standing with one’s friends, casting insult—changes one imperceptibly in one direction or the other. It is the sum of innumerable unthought-of actions that produce the dramatic change in phenotype.
Absolutely no one is happy with this situation.3 Elves, thinking themselves (often rightly) so very virtuous, want no mention made of any relation to that most brutish of humanoids. These are the bedside whispers given to little elflings: “Be good, or your sins will show themselves on your hairy body!” Everyone knows, or thinks they know, someone who has fallen; one day, someone disappears, is never seen again. It is said, if anything is said, that they killed themselves, a less-embarrassing story. A whole line can be besmirched by the fall of one son. What does it say about you, they’ll mutter when your back is turned, that you raised a son so wicked that he turned into a beast?
The orcs don’t much care for it either. For a people built on strength and ruthlessness and a narrow-eyed focus on getting things done, any kinship with the effeminate lightweights is a snub, like the birth of nearsighted runt. But where an elf making the turn quietly disappears, self-exiling into either a period of contemplation in an attempt to reverse the process or a rampage free of the oppressive strictures of elven society, an orc turning slight will, with any sense, just disappear into the night. Those with less sense will awaken—for a few sputum-gasping moments—with knives lodged between their ribs. So hated are the elves, and those looking as though they will turn to one, that any sign of wasting or emaciation or weakness will often be taken as the turn, and culled nonetheless.
But the turn is a slow one, and is a progression along a spectrum rather than an on-off switch. Hence, half-elves and half-orcs. They would like to have you believe that these folks are the result of forbidden love or more vicious abuse, but that’s a façade all pretend to. A half-elf or half-orc is simply an intermediate step along the spectrum. A fallen elf slowly gains strength and loses some grace, and becomes what is commonly called a half-elf. The process continues from half-elf to half-orc, and from half-orc to orc. And these poor folks have the worst of both worlds, hated from all ends for not being enough . . . whatever “enough” means. Is it any surprise that such people tend to the extreme, either paragons of goodwill or redoubts of perfidy, in an effort to become all one or all the other?
Orcs are, by definition, evil. Elves are, by definition, good. An elf who does evil becomes strong and coarse and brutish. An orc who does good becomes slim and graceful and clever. Can there be any surprise that they—flip sides of the same coin—hate each other so? The sight of the other reminds each of what they could become if they stray from their path. There is no thing so hated as the incarnate reminder of one’s own shortcoming.
The Prince, Niccolo Machiavelli.
Some acts of enormous import—saintliness or atrocity—can change one much more quickly. It is these sudden transformations, typically an elf turning into a beast overnight, that are what most commonly betray the truth of the matter to outsiders.
This is a lie. There are some remarkably well-informed sages who both know of this situation and that that it is, intellectually, interesting as shit. They don’t get out much.