"InuYasha: Kuroi Tessaiga" is a three-episode anime OVA that serves as a sequel to the original "InuYasha" series, focusing on the aftermath of the battle with Naraku and the challenges faced by the main characters. The story begins with InuYasha and his companions—Kagome, Miroku, Sango, and Shippo—continuing their journey to restore peace to the feudal era. However, a new threat emerges when the Black Tessaiga, a corrupted version of InuYasha's powerful sword, is created. This dark blade is born from the remnants of Naraku's evil energy and possesses the ability to consume InuYasha's soul, threatening to turn him into a mindless demon.

The Black Tessaiga's influence begins to manifest as InuYasha struggles to control its power, leading to internal conflict and tension within the group. Kagome, determined to save InuYasha, seeks a way to purify the sword and free him from its grip. Meanwhile, Miroku and Sango confront their own challenges, including lingering emotional scars from their battles with Naraku. The narrative explores themes of redemption, the struggle between good and evil, and the bonds of friendship as the characters work together to overcome this new danger.

The OVA delves into the psychological toll of wielding such a destructive weapon, highlighting InuYasha's vulnerability and the strength of his relationships with his companions. The resolution hinges on Kagome's unwavering faith in InuYasha and her ability to reach him even as the Black Tessaiga threatens to consume him entirely. The story concludes with the group reaffirming their unity and resolve to face future challenges together, leaving the door open for further adventures in the "InuYasha" universe.