A secret sword with an incredibly long blade. While the truth is unknown, it is described in a variety of legends. One famous lore says that the sword grants power and luck to those who have sworn revenge. Its edge is unusually sharp and as befitting the legend, it clouds and enrages the mind of its wielder.
When loosely translated into English, Kagekiyo comes to mean "Pure Shadow".
This sword is most likely named after Taira no Kagekiyo, the protagonist of the Namco arcade game Genpei Tōma Den (The Genji and Heike Clans), in which a resurrected Kagekiyo returns from Hell to seek revenge against Minamoto no Yoritomo and the Genji Clan.
Historical Taira-no-Kagekiyo was a noble aristocratic knight and a womanizer, but after his defeat, his hatred against the Minamoto clan and Kamakura Bakufu were so great that he burned his own face and concealed his sword as a shikomizue... the name of this sword was Azamaru, and it's polished surface like a mirror allowed Kagekiyo to always have a look to his burnt face, symbol of his hatred. Because of the tragedy it lived thru, the katana Azamaru was said to have become a Yōtō 妖刀 a yokai in form of a sword. Kagekiyo appears ad a main role in the Nogaku piece Yashima.