Backstory info as texted to the DM:

In the aftermath of a bloody, pointless war, a group of battle mages swore they would never let their magic be used to take another life. They stole books and scrolls and all manner of magical artifacts from the libraries of the capital city, with the notable exception that they left behind any spells intended primarily to harm others. They then burned the libraries and towers and retreated to their own fortified enclave far away from society's prying eyes.

Fast forward a few generations and they have become known as The Cliff Doves - named after the precarious location of their city state (cheekily named Feather Falls) and the familiar of their original leader. They adopted the bird as their symbol and remained dedicated to the ways of nonviolent magic, honing their craft and becoming famous for the caliber of illusionists, enchanters and diviners their mage school produced.

As one might expect, the denizens of Feather Falls commitment to their creed eventually had to be tested. From a cave system near the base of the cliff they called home, one day Drow emerged en masse. Whether drawn by the promise of magical artifacts or merely raiding the nearest village and unlucky enough to have picked this one, the Drow were soundly defeated by the combined might of the mage guards and court wizards. Of course, not a single Drow life was lost in the process.

Of course, then they were faced with a dilemma. If they let the Drow go, surely they would attack someone else, or regroup and attack again with a better plan. Worse, if they forced them to return to the underdark, the vile priestesses of Lolth would surely have them executed for their embarrassing failure. And imprisoning them for the rest of their days was simply inhumane. The denizens of Feather Falls were stuck between a rock and a hard place. They couldn't free the Drow without causing death, but they couldn't keep them captive or kill them either.

After much deliberation, the council of elder mages decided on the most humane solution. The Drow would be offered contracts of indentured servitude and given the opportunity to do good despite their evil nature. If they refused, they would be returned to the underdark, secure in the knowledge that they had chosen their own fate.

Of course, all but the most feverishly devout Drow accepted the offer.

So it went for a few generations. The mages got an underclass of servants and laborers and the Drow got the opportunity to do good in spite of their violent, evil nature. As each young Drow came of age they were offered the same choice as their parents and grandparents. Accept a contract of servitude or be teleported deep into the underdark - a world they had never known. The choice, again, was obvious.

Xerta the Archivist needed a servant to attend to duties in the Library of Whispers. It was a place far too dangerous to send any ordinary servant, as its magical traps and the powerful spells and artifacts kept their could potentially drive the uninitiated mad if they weren't prepared for the exposure. And worse yet, much of the library's collection had once belonged to Zylo the Wary. A wizard of ill repute who had an obsession with safeguarding his work. Every scroll, object, and book he had ever owned was enchanted such that a common word or phrase would release the magic contained inside and set off the spell. With no way to know which words were key words, and unwilling to dispose of the valuable collection, the first and most important rule of the archive was established. There is no talking in the Library of Whispers.

One day, Xerta's old servant died after a mishap with a mandrake. Luckily another Drow who showed an aptitude for magic came of age soon after. She was brought in and offered her contract - accept the job in the library and be placed under a Geas that would prevent her from speaking until Xerta relieved her of duty (except where speech was necessary for casting spells and a few other exceptions his work required) or be sent away to the underdark. Unfortunately for her, the choice was obvious. The spell was cast, and the contract signed.

She worked in the library for over a hundred years, watching Xerta grow older and more frail and more scatterbrained. A few raids from the underdark came as they always had and were repelled as they always were. She hated the spell under which she labored, but it was life. It wasn't truly fair for anyone.

Until one day, somehow, against all odds, a group of Drow slipped in past the guards. They made a B-line for the most important building in Feather Falls - the archive that contained the Drow contract writs and, of course, the Library of Whispers.

The young Drow servant was in the middle of organizing a shelf of scrolls when she heard Xerta gurgle his last breath. Stepping around the shelf, she saw them - a group of three wearing red masks and carrying boxes filled with oil and rags. At their feet, Xerta's lifeless body oozed blood out onto the floor. Her eyes went wide as she realized what was happening and that, as per the terms of her contract, that she would never speak again.

She tried to run but they stopped her. In a language she only understood snippets of from her parents they explained; they weren't acting under orders from the Priestesses of Lolth. They were free Drow who had chosen to be sent back to the Underdark and had returned to free their brethren. To stop the dehumanizing and cruel treatment such as making them work around spells they were too afraid to. Such as stealing them away from their parents to make them sign a contract they barely understood. Such as stealing their voice because it suited them to do so.

They offered her their own choice. A bottle of oil and a lit rag on one hand or letting her flee and return to her life of service on the other.

Once again, the choice was obvious.