Crescent Blade

The Crescent Blade is a magic sword created by the Goddess Eilistraee out of "moon metal." The blade is curved, resembling a crescent moon attached to a hilt. Eilistraee created the blade with the eventual intention of killing Lolth. As such, the weapon was enchanted to sever the neck of any creature, any, including deities. The Crescent Blade was originally recovered by Halisstra Melarn, hidden in the belly of a purple worm. Halisstra later lost the blade in the Demonweb Pits, but it was recovered by the Darksong Knight Cavatina. The blade's awesome power was used to sever the necks of both the demigod Selvetarm and Eilistraee herself. Through Lolth's manipulation, Eilistraee was killed by the very blade she crafted to kill Lolth.

Lisa Smedman. Ascendancy at Last. Wizards of the Coast.