Akahoshi

is a ninja from Hoshigakure in the Land of Bears.

Background
He took over after the Third Hoshikage suddenly "grew ill" and died. In truth, he and his followers Shiso and Yotaka murdered the Third Hoshikage. He thought that with the powers from the meteor, their ninja would become invincible and they could compete with the five main countries. When he never told anyone about the side effects of the star training, some of the villagers went against him as Natsuhi and Hotarubi try to hide the star.

Hoshigakure arc
Some time later, Akahoshi called upon the services of Team Guy and Naruto Uzumaki to help protect the meteor. He later posed as the mysterious masked ninja and managed to kidnap Sumaru to lure out the mysterious bandit to use as bait for Natsuhi. When Natsuhi arrive, she and Akahoshi battled each other as Akahoshi sends Shiso and Yotaka to fetch the leaf ninja. Akahoshi used his Mysterious Peacock Method: Beast to knock Naruto and Natsuhi into the Valley of Death, which they managed to secretly get out of using the Mysterious Peacock Method: Wings. Akahoshi told Neji Hyuga that Naruto got in the way and that their mission is over.

Akahoshi's true colors were shown to the leaf ninja when Rock Lee and Tenten find Sumaru in his quarters hospitalized and rescued him. Later Naruto and Natsuhi tracked them down by tracking her chakra trail. Akahoshi claimed the meteor after using Sumaru to force Natsuhi to surrender it. Akahoshi later laid a trap at the Star Training Building the which resulted in Natsuhi's death.

Akahoshi later gave orders to the adult ninja to eliminate Sumaru, Hokuto, and the leaf ninja shinobi at first sight. Akahoshi later had the adult ninja fire arrows at the Star Training Building that Sumaru was mourning Natsuhi in. When Hokuto and Mizura exposed the side-effects of the Star Training, the adult ninja turned against Akahoshi. Akahoshi proclaimed that he was the Fourth Hoshikage and planted the meteor in his chest to get the meteor's ultimate powers. None of the ninja could defeat him until Naruto used the Rasengan to destroy the meteor and defeat Akahoshi with the help of Natsuhi's ghost who was able to save Sumaru. Though he is a prisoner in his own village, Tsunade mentioned that he, Shiso, and Yotaka will be subjected to "severe punishment".

Trivia

 * His name means "red star" ("aka" meaning "red" and "hoshi" meaning "star").
 * He bears somewhat of a superfacial resemblance to Nadare Roga, a Yukigakure ninja from the first Naruto movie.