Dark Moon Greatsword

Obtaining

 * Received at the end of Ranni the Witch's questline.

Trivia

 * The Dark Moon Greatsword is an iteration of the Moonlight Sword, a recurring weapon that has appeared in almost every FromSoftware game since the first King's Field title in 1994.
 * The "long-standing tradition" in the description could also be a reference to the Moonlight Sword's reappearance.