Azamaru

is the second Noble Phantasm of Taira-no-Kagekiyo
It is used as a normal weapon. There should be only one, but for some reason they have two. 
The beloved sword of the Heroic Spirit, Taira no Kagekiyo. A Noble Phantasm.
Originially, it was a Tachi passed down in the Taira family.
In time of peace, it takes the form of the twin swords Azamaru, however, when its true name is released, it returns to its true form as one single Tachi.
It is something that runs on deep-seated grudges, the agglomeration of grudge itself. A living lord who touches it would not come out unscathed.
When Kagekiyo takes it out, I would have to be greatly cautious of it and keep my distance, wouldn't I?
......However.
As long as she remains Yoshitsune, she would not let any harms come to Master.
Certain mythsあざ丸 - Wikipedia posit that it may be the same sword as Daitouren—one of the Noble Phantasms of Suzuka Gozen.
Category:Noble Phantasms
Category:Unknown rank Noble Phantasms
Category:Unclassified Noble Phantasms
Category:Swords
Category:Noble Phantasms introduced in Fate/Grand Order
Category:Noble Phantasms of Ushiwakamaru (Minamoto no Yoshitsune)