This post from 2016 is more recent than my usual revisits, but I had forgotten about it, only coming across it while looking for another post and thought it was worth a reshare...
What humans mistake as different tribes or clades of elves are actually different stages in their millennia long, perhap endless, lives.
Wood elves are elven adolescents. They rebel against their parents and go to live in bands of others of their age. They throw racuous parties in the woods and experiment with intoxicants. They are capricious, emotional, and cliqueish. Their tribes run the gamut between Woodstock and Lord of the Flies.
High elves are elven adults. They interact most with other species and are responsible for the maintenance of elven civilization. It is in this age cohort that the immortality of elves begans to take its toll, however. Elven brains are not structurally that different from humans. They do not have the capacity to hold countless centuries of memories. Their initial compensatory mechanism is monomania. Elves develop a strong interest that narrows the array of factual information they must recall and provides constant reinforcement for the things they find important. Some become swordsmasters, some master artists or craftsmen, some archmages.
For some elves this is enough, and they grow more skilled, more focused, and stranger, until they become almost demigods in their chosen vocation. These are the Gray.
Others, though, are not able to maintain such focus. Something akin to dementia sets in. They become forgetful, and paranoid. As they begin to lose their past--lose themselves. They find only intense linger long. These are the drow, the dark elves.
Dark because of the darkness that consumes their minds; dark for the deeds they commit to hold on to self and not slip into endless reverie. They go to live in the dungeons of their kind to pursue intense pleasures and horrors or simply howl or cackle in the darkness. These elders are feared by other elves. They avoid them and will not reveal their relationship to them to non-elves.
2 hours ago