In the Naruto series, the ultimate fate of Sasuke Uchiha's Kusanagi Sword is not explicitly addressed or shown. The series does not provide specific information about what happens to the sword after Sasuke receives it from Orochimaru.

As the narrative progresses, Sasuke's focus and priorities shift, leading to changes in his character and his journey. While Sasuke initially wields the Kusanagi Sword and incorporates it into his combat style, the series does not delve into the sword's destiny or its subsequent significance to Sasuke's story.

It is worth noting that the Naruto series primarily focuses on the characters' personal growth, relationships, and the overarching plot, rather than providing exhaustive details about specific objects or artifacts. Therefore, the fate of the Kusanagi Sword remains open-ended and is left to the viewer's interpretation.