FOR2 The Drow of the Underdark, 2nd ed., p. 46-47 wrote:
The High History of the Drow
The history of the drow in the Realms is long and grand, but very murky to the sage or interested inquirer of today. Truth has been willfully twisted by clever and fanatical drow to serve many partisan noble House interests and the major drow faiths. It is usual in Loth-dominated communities, for example, to pretend that traitors to the Goddess, or vanquished noble Houses, simply "never existed." Although this is a hollow deceit at the time, it effectively "rewrites history" by four generations later. The history of the drow can thus only be recounted in general terms - following the work of Shahaerynus, a drow sage who dwelt in long-ago Myth Drannor, and complied The High History of the Drow. What you are about to read are excerpts from this book., Susprina, Elminster tells us, he is currently working on a sequel.
We know very little of the Ilythiiri, or "Elves of the South," before this crucial event. Even then, they were known as "Dark Elves," for the hue of their skins. They dwelt in the jungles and hot forests of the South. A proud, warlike, culturally advanced (some sages or elven peoples say "decadent") folk, the Ilythiiri attacked all neighbors, including other elven tribes. Their cruel raids and depredations, ordered by warlike nobility and clergy of their two cruel deities, Ghaunadaur and Lolth, forced elves, humans, dwarves and others to ally against them
Defeated in a series of titanic magical battles, the dark elves fled into underground warrens they had earlier discovered. This event, known as "the Descent." marked the end of the drow as a surface dwelling race.
The Dark Wars
The warlike drow nature did not change when they escaped their surface foes. They immediately launched a series of wars to establish territories in the Underdark. They began by stealing and seizing dwarven magical items, and using them against the dwarves - establish an enmity that is still strong today.
The drow then fought among themselves, noble against noble, priest against priestess, for rule of their new realm. This all-out war ended amid great magical explosions that brought down the roof of the largest dwarven cavern they had seized, great Bhaernden. The ceiling collapsed entirely, burying many drow and the shattered dwarven cities. The cavern, now open to the sky, became known as The Great Rift. The surviving drow nobles gathered what people, slaves, and equipment they could seized, and fled into the Underdark in search of places to dwell. "The Scattering" brought about the many rival, self-interested cities where most drow live today.
The Drow Today
Drow still hate each other, and strive fiercely to eradicate or weaken those of rival cities, clans, noble Houses or faiths. This constant strife keeps other races far safer than they would otherwise be, as the drow (urged on by clergy of their gods) fight among themselves, rather than launching new wars on others.
Some few (perhaps 15% of all) drow are deemed "good" (actually, most are better described as Lawful or Chaotic neutral in alignment) by other races. They look to the surface, and worship Eilistraee, turning their backs on the darkness their brethren have embraced.
It is not easy for a drow with a peaceful disposition, or feelings towards what most surface dwellers deem "Good." to develop a strong personal morality or even survive for long in the cruel twisted societies of drow cities. Only truly outstanding individuals (Drizzt Do/Urden, for example) manage to win free of drow lifestyle. They are the heroes - and usually, the wander adventurer-outcasts - of the race.
No "good" drow is yet known to have succeeded in turning the bent of a drow city towards good. Altering the smallest customs and (dis)courtesies is impossible without tht approval and support of Lolth, who dominates most such societies. City dwellers are ruled by fear, deceit, and cruelty; it is impossible for them to act other than as the "dark villains" surface Realmslore makes them out to be, as long as they remain the cities of the Underdark. Drow who leave cities are dismissed and ignored - except by drow merchants, who are glad to have drow surface contacts.
Drow who dwell in small roving bands however, or who reach the surface and manage to establish and existence there, can and have adapted to local mores and conditions - and exhibit natures no more good or evil than the general run of humankind.
Initial daytime exposure to the surface world usually blinds drow [DM's NOTE: apply "Total Darkness" effects to them, as though they were human; if they bind their faces, they fight as in "Starlight." as detained in the "Darkness" section of Chapter 13, "Vision and Light," of the Dungeon Master's Guide). Drow who are prepared for the effects of sunlight, and who have practiced fighting by sound alone, can reduce these penalties. (DMs must adjudicate this on a case-by-case basis, following a general rule that the drow will be quite effective against opponents within arm's reach, and vastly less so, the further away fores are.)
Initial daylight surface exposure is also likely to give drow horrific sunburn. After an initial attack, this burning quickly lessens, but drow will always prefer to keep their skin and heads covered during daylight hours.
Drow who adapt to the surface always remained comfortable in darkness, and able to see at night as well as a cat does. They also retain a lithe agility, a dislike of bright lights, open sky, and loud noises. They also have an unparallelled viciousness in battle. The detrimental effects of light on drow (detailed in their Monstrous Compendium entry, and in this book, in the Magical Items chapter under "Attunement") fade slowly; all negative modifiers are reduced (toward normality) by 1 point for every year of continuous surface-dwelling. If the drow remains on the surface for at least one year after all negative effects cease, they will never return, and the individual can thereafter operate freely both underground and above ground. ("Surface dwelling" does not preclude sleeping in caves, exploring cellars, tombs, dungeons and other underground areas for periods of less than four continuous days, or dwelling indoors and avoiding direct sun.)
Some drow have built successful trading careers in Waterdeep, Calimshan, Chessenta, and Mulhorand. Others are known to lurk in the dark depths of The High Forest and The Far Forest, or trade with Zhentil Keep's merchants in the woods northwest of Shadowdale.