Mimihagi

Mimihagi is a fallen god that operates in the outer areas of Eastern Rukongai and acts as the right hand of the Soul King.

Appearance
Mimihagi takes the form of a humanoid entity with a body shaped like an arm and a clenched fist, and a single, large eye on the back of the fist. It wears a simple tunic and has a large band encircling the area behind the fist.

History
When Jūshirō Ukitake was three years old, he developed a lung disease, which caused the doctors in the area to abandon him when they could not treat it. His parents took him to Mimihagi's shrine and prayed for Mimihagi to take his lungs away, which Mimihagi did. This allowed Ukitake to survive and become a Shinigami.

The Thousand-Year Blood War arc
During the second invasion of the Wandenreich, Ukitake activates the Kamikake in preparation for becoming the right hand of the Soul King. When the Soul King dies, Ukitake begins the process of replacing him by allowing Mimihagi to take the rest of his body, which will allow him to replace the Soul King in exchange for his life. As he does this, a shadow resembling Mimihagi begins rising off his back before extending toward the sky as Ukitake screams in pain.

Powers and Abilities
Life Extension: Mimihagi can allow an individual to survive an otherwise fatal disease by taking the afflicted portion of their body from them, though this will lead to irreversible side-effects for the rest of their life; Ukitake had his diseased lungs taken from him, but in return he frequently coughs up blood and becomes too sick to fulfill his duties as a captain.

Kamikake: An individual who has had part of their body taken by Mimihagi can sacrifice the rest of their body and their life in exchange for replacing Mimihagi in the role of the right hand of the Soul King. Initially, the Kamikake changes the user's shadow into something resembling Mimihagi itself. Later, the shadow will spread across the user's entire body before stretching toward the sky in the shape of a hand.