Black Hiraikotsu

Black Hiraikotsu is a

Hanyō no Yashahime
When Inuyasha and Kagome return, Sango explains to her identical twin daughters that the time finally came for her to make use of the "Black Hiraikotsu" which she had been secretly forging and further strengthening with the help of Kin'u's ever developing spiritual abilities and Gyokuto's innate expertise in craftsmanship. This means that its abilities are considerably stronger and more effective towards their targets as they are deadly. She is seen carrying it on her back as she fetched her husband from his thousand-day spiritual training period.

A horde of yōkai later swarm toward Sango, as she is ready to display its unmatched demonic abilities to destroy them.