Yomi

was an evil medical-nin who appeared in Naruto: Shippūden the Movie. He came from a long line of followers of Mōryō who had spent generations perfecting a dark form of medical ninjutsu.

Plot overview
At the beginning of the movie he gave his men, The Gang of Four, special chakra enhancement by infusing them with dark chakra snakes, thus giving them access to jutsu they could not normally use. After his men had taken down the guards of Mōryō’s prison, Yomi then entered Mōryō's spirit cave and freed him. He then offered his body as a spirit container for Mōryō until they could retrieve Mōryō's body. When Kusuna reported that Gitai had been killed by Lee, Yomi made it clear that he didn't care, instead telling Kusuna to kill Lee, along with his friends and Shion. This resulted in Kusuna and the rest of The Gang of Four being killed. Shion then confronted Yomi, and prepared to seal Mōryō. Yomi interfered, but Mōryō wanted to take matters into his own hands and burst out of Yomi's body, subsequently killing him. Yomi's body then fell into the lava after the volcano erupted.

Abilities
Yomi was shown to have great expertise in medical ninjutsu. He could enhance the chakra of anyone he wished with ease, allowing them to fight for longer periods of time and to perform more powerful jutsu. His skill in medical ninjutsu was great enough to effectively (although only for a limited amount of time) use his body as a container for a demonic spirit.

Trivia

 * "Yomi" means underworld.