The blade was curved, resembling a crescent moon attached to a leather hilt. There was silver inlaid in the blade. On it were Drow words that translated to "Be your heart filled with light and your cause be true; I shall not fail you." When wielded, the Crescent Blade spouted crimson fire.
The blade's enchantments included moonlight—it could cut through armor and stone—protection against evil, and being able to strike quickly. If the wielder was a true priestess, she could use it to sever the neck of any creature, including gods. 
It was said that Eilistraee plucked a pebble from the heavens and tossed it to the earth. It grew as large as a boulder and very hot. It was made of moonmetal; if one looked at the moon, they could see a hole in the shape of a crescent. The boulder was forged into a crescent-shaped blade with enchantments.
The Crescent Blade was wielded by Mathira Melarn, one of Halisstra Melarn's ancestors and an Eilistraeean Sword Dancer from Ched Nasad. Mathira was last seen in Harrowdale, making her way to Black Feather Bridge.
About 1373 DR, Halisstra Melarn, a new convert to the clergy of Eilistraee, was charged with recovering the Crescent Blade and using it to slay the goddess Lolth herself. Halisstra, secretly followed by Ryld Argith, found the blade in the belly of a purple worm that had swallowed Halisstra. She was able to use the blade to cut her way free.
Halisstra made her way to the new Demonweb Pits, where she was confronted by Danifae Yauntyrr, to be the Yor'thae of Lolth. During the fight, the Crescent Blade was broken and was left where it fell.
After becoming Lolth's Lady Penitent, in 1375 DR Halisstra Melarn informed Qilué Veladorn (leader of the Church of Eilistraee) and Cavatina Xarann (a Darksong Knight) about the whereabouts of the Crescent Blade. Cavatina was dispatched to the Demonweb Pits to retrieve the sword, which she found intact. However, the weapon was no longer the same weapon that Eilistraee had crafted, instead it became a vessel for a balor Wendonai. Nevertheless, the sword was used by Cavatina to kill the demigod Selvetarm.
After that, the Wendonai-possessed Crescent Blade was brought to Qilué Veladorn, who struggled against the balor's influence, as he tried to corrupt her by leading her to think that she would have been able to kill Lolth with the sword. Qilué's will was however not defeated by Wendonai, and she devised a plan to use the sword to kill him permanently. She intended to summon the demon and then take him into herself, destroying him with Mystra's silver fire. If successful, she would have freed the drow from the demon's influence, and in 1379 DR, with that goal in mind, Qilué and her sister Laeral Silverhand traveled to the only place where such a task could be accomplished: the royal court of ancient Ilythiir, where Wendonai was summoned for the first time.
Fearing that Qilué would lose her life in the ritual, Laeral froze her in time and went to seek help, but in the meantime the drow priestess was found by the Lady Penitent, who took hold of the Crescent Blade. Cavatina Xarann, who had also reached the ruined court, was killed by the Lady Penitent, who shortly after took Qilué's life as well. In fact, Eilistraee inhabited the body of her chosen to try to free Halisstra from Lolth's influence, but Wendonai tricked her into killing Qilué (and, apparently, the Dark Dancer alongside her) before that could happen. However, by that time, the sword no longer had the power to destroy souls (Cavatina's soul being still intact after the sword struck her was an example).[note 1]
Freed from Wendonai, during the Dark Maiden's absence, the Crescent Blade was then powerless. However, after Eilistraee's return during the Second Sundering, its status remained unknown.[speculation]
- ↑ In one of his answers, Ed Greenwood states that the Crescent Blade wasn't able to kill Eilistraee, and that she actually managed to survive, albeit much weakened. When Qilué Veladorn was killed, the sword didn't destroy her soul, which was instead dragged into the Weave (the souls of Mystra's chosen often become "Voices in the Weave" after their death, as explained in the novel Spellstorm, and their memories and experiences are shared by Mystra). Since the goddess was inhabiting her body, a great part of her power was also dragged into the Weave with the Chosen's soul. After that, for about a century, Eilistraee could only manifest herself as a floating black mask surrounded by moonlight, capable of silently communicating with mortals, but not of answering prayers or granting spells (except by direct touch). After Mystra and the Weave were completely restored in 1487 DR, the goddess of magic could finally give Eilistraee her own lost power.
- ↑ 1.0 1.1 Lisa Smedman (February 2005). Extinction. (Wizards of the Coast), pp. 280–282. ISBN 0-7869-3596-0.
- ↑ Lisa Smedman (February 2005). Extinction. (Wizards of the Coast), pp. 334–335. ISBN 0-7869-3596-0.
- ↑ Paul S. Kemp (February 2006). Resurrection. (Wizards of the Coast), p. 305. ISBN 0-7869-3981-8.
- ↑ Lisa Smedman (February 2005). Extinction. (Wizards of the Coast), p. 261. ISBN 0-7869-3596-0.
- ↑ Lisa Smedman (February 2005). Extinction. (Wizards of the Coast), p. 260. ISBN 0-7869-3596-0.
- ↑ Lisa Smedman (February 2005). Extinction. (Wizards of the Coast), pp. 284–286. ISBN 0-7869-3596-0.
- ↑ Lisa Smedman (February 2005). Extinction. (Wizards of the Coast), pp. 330–331. ISBN 0-7869-3596-0.
- ↑ Paul S. Kemp (February 2006). Resurrection. (Wizards of the Coast), p. 344. ISBN 0-7869-3981-8.
- ↑ Lisa Smedman (January 2007). Sacrifice of the Widow. (Wizards of the Coast), pp. 184–186. ISBN 0-7869-4250-9.
- ↑ 10.0 10.1 Lisa Smedman (January 2007). Sacrifice of the Widow. (Wizards of the Coast). ISBN 0-7869-4250-9.
- ↑ 11.0 11.1 11.2 11.3 Lisa Smedman (June 2008). Ascendancy of the Last. (Wizards of the Coast). ISBN 978-0-7869-4864-2.
- ↑ Lisa Smedman (June 2008). Ascendancy of the Last. (Wizards of the Coast), p. 287. ISBN 978-0-7869-4864-2.
- ↑ Kim Mohan ed. (2015). Sword Coast Adventurer's Guide. (Wizards of the Coast), pp. 23, 108. ISBN 978-0786965809.
- ↑ Ed Greenwood (2016-06-07). Death Masks. (Wizards of the Coast). ISBN 0-7869-6593-2.