Ranmaru

is a young orphan from Kirigakure. He was loyal to Raiga Kurosuki of the Seven Ninja Swordsmen of the Mist. Ranmaru has an androgynous appearance and a soft, almost feminine voice (in the English dub, he has a female voice actor).

Background
Ranmaru grew up with a weak body, but the farmers living near him gave him food to survive. One day, he used his kekkei genkai, and accidentally revealed witnessing an injury that he otherwise could not have seen. The villagers realized that he was strange and stopped feeding him. Ranmaru became lonely after a while. Not long afterward, Raiga arrived in the course of a mission, and was planning on killing Ranmaru, but Ranmaru revealed his ability and his perception of the sorrow within Raiga. Raiga then carried him on his back, allowing Ranmaru to see the outside world. After Raiga's defection, he and Raiga enslaved a town and forced its villagers to work in its mines, also assembling some followers (including Karashi) to form the Kurosuki Family.

Curry of Life arc
Ranmaru was first introduced spotting Rorusuke's party escaping from Katabame Kinzan for Raiga. Raiga and Ranmaru then fought Naruto Uzumaki and Team Guy (minus Guy himself) when they arrived to defeat the Kurosuki family. Raiga initially gained the advantage due to Ranmaru's abilities and his powerful lightning jutsu, but after Ranmaru was knocked away from Raiga, Raiga became distraught over losing him, and Naruto knocked him off a cliff. Ranmaru then revealed his role and past to the Leaf ninja and asked to die. Naruto's group left him in a small shed on the mountain and took him back to the Curry of Life Shop after defeating the remaining Kurosuki family members.

Karashi took Ranmaru on his back, and then brought him to Raiga, who wasn't dead yet. Ranmaru revived him with his chakra, but then passed out, seemingly dead, from doing so, which caused Raiga to demand that Karashi bring him the Leaf ninja. Tenten discovered that Ranmaru was alive, and brought him to a shed in the middle of a thunderstorm, trying to bring down his fever. While Ranmaru was willing to die, Tenten told him that he didn't deserve to decide that, as the people he helped Raiga kill could not make that decision. Ranmaru recovered his health, and became able to walk after eating the Curry of Life, and wished for Raiga to eat it.

Ranmaru accompanied Tenten, Sanshou and Karashi to the mountain where Neji, Lee, and Naruto were fighting Raiga, and fed the wounded ninja the curry. Ranmaru returned to Raiga and using his mist, tried to trick him into walking over a cliff in order to atone for his actions. The plan failed when Lee attacked and interrupted Raiga, and when Ranmaru attempted to convince Raiga to stop the battle, Raiga believed that Ranmaru had betrayed him. Naruto rose to protect Ranmaru, and punched Raiga off the cliff through successive attacks with shadow clones. Raiga realized how Ranmaru could never be a truly free soul as long as he depended on him, and gave himself a funeral in one of his more coherent moments. As the arc comes to a close, Ranmaru becomes an apprentice at the Curry of Life shop.

Unknown Kekkei Genkai
Even though he was apparently paralyzed, Ranmaru's Kekkei Genkai gives him the ability to see through walls and every object in front or in every angle like the Byakugan, cause illusions, and interferes with even the Byakugan. He can also use some other vaguely defined powers relating to vision. This bloodline does not have a mentioned name, but when used, Ranmaru's eyes glow red. Ranmaru's powers seem to be the most broad of any kekkei genkai, ranging from perfect illusions to the ability to transfer lifeforce to bring someone mostly dead back to life.