Ne no Kubi (根の首, "Root Head") is the main antagonist of InuYasha Since Then, a special manga chapter.
History
Ne no Kubi was a root yōkai that once was sealed by Kikyō 50 years ago, before she met Inuyasha. It was freed due to the collapse of a mountain and it killed people in order to regain its strength.
Its main motive was to search for Kikyō and to obtain the Shikon no Tama, a jewel that disappeared from the world after Naraku's defeat. Ne no Kubi was sealed for a long period and did not know that Kikyō was no longer alive.
Kagome, who had a similar appearance to Kikyō, received a sudden attack from Ne no Kubi to obtain the jewel. In the end, with the head wounded by Kagome's sacred arrow, it was eliminated by Inuyasha's Kaze no Kizu.