Yama

A being that is used by a wielder of the Rinnegan. This figure, like the Animal Path's summons, possesses Rinnegan eyes, allowing a Rinnegan wielder to see through its eyes. It appears to Raido not only in its true form but also as a spirit guide to assist him on his travels and enlighten him on the Paths along the way.

Personality
Yama is portrayed as a stern and "by-the-book"of person. He is constantly aggravated by Raido's humor, something he greats personal offense to. He often expresses his hatred of the Uchihas' ability to turn a grave situation into a joke for his own amusement. Something that has been seen as an on running gag between the two. He also prefers to be addressed with honorifics, something which all except Raido do another trait that burns him up. However he is and almost omni-present as often quotes he has seen it all as the King of the Dead. Despite his disaccord for the Uchiha's personality he does harbor respect for the mans intelligence and abilities. Even going as far as stating Raido could be one of the greatest shinobi who ever lived, if he only stopped fooling around.

Abilities
He is used by the Naraka Path for interrogation and is capable of discerning whether an individual is lying or not. When implemented on a target, a serpent-like apparition of their life force energy, in the form of an enlarged tongue emerges from their mouth and is presented to the figure. The King of Hell then proceeds to pass its judgement on the victim. If they are lying (or refuse to answer the question), their life force energy is ripped out by its two hand-shaped tongues and consumed, leading to the victim's death. If the target is telling the truth, it lets go of the protrusion leaving the target alive but extremely exhausted. The King of Hell can only be seen by the ones it's being used upon. For its second ability, the King of Hell can repair the other Paths, should they be damaged or killed. When it consumed the remains of the Asura Path, the path emerged from the figure fully restored and was even wearing a new Akatsuki robe (the body had discarded its previous robe). While the King of Hell is being used for this, it seems that others are able to see it, unlike when it is being used for interrogation purpose. Both Naruto while in Sage Mode and Itachi Uchiha, who managed to blind it, were able to see it.

Lastly, he can be summoned for the Outer Path: Samsara of Heavenly Life Technique, where Nagato can release life force energy to people who were recently killed and allow their souls to return to their rejuvenated bodies. This technique can only be used by Nagato, the main entity in control of the seven paths. This power is said to transcend even the very concepts of life and death.