Magatsuhi

Magatsuhi is the youkai who killed Midoriko and whose soul with whom she continuously battles inside the jewel. Like Naraku, Magatsuhi was created by a corrupt human who lusted after a priestess and allowed his body to be consumed by youkai; however, unlike Naraku, who retains a humanoid form, Magatsuhi's true form is much more monstrous. Magatsuhi is first seen in manga chapter 89 as the mummified corpse of an unnamed but massive demon. Later in the manga, the demon's name is revealed to be Magatsuhi, and it is able to (temporarily) escape the jewel and create a humanoid body out of some of Naraku's spare parts; however, this body was soon destroyed by Sesshomaru and InuYasha.