This weaponskill's name in the Japanese version is:
十之太刀・乱鴉 (Ju no Tachi: Rana)
乱 (ran): disorder; disturb; riot; war
鴉 (a): crow; raven
This might then be translated: "Tenth Style of the Tachi: Crow of War", which would be appropriate given the actual historical background of the Kogarasumaru, the Samurai Mythic Weapon. Around the era of the Kanmu tenou, it is rumored that a gigantic crow came to his majesty holding Kogarasumaru.