Yūkimaru

is a young boy (it is still unknown if he is a shinobi) who appears in the second Naruto Shippūden filler arc. He is a test subject of Orochimaru, because he has the ability to control the Sanbi.

Hunt for the Three-Tails Arc
When Sasuke Uchiha trains, he cuts off tree flowers with his Chidori. After that we can see Yukimaru collecting the flowers. Sasuke tells Yuukimaru to go home and he replies he has no home to go to. Later on Kabuto sets off together with Yuukimaru for a journey. They eventually arrive at a dark swamp. There, Kabuto conducts an experiment where he forcibly releases the full power of Yukimaru's chakra. This results in a strange creature (possibly the Three-Tailed demon) to partial emerge before submerging again. Afterwards, Yukimaru is left exhausted, but Kabuto finds the results satisfactory. Later on the way back to Orochimaru's lair, Kabuto lets Yukimaru take a rest at a hot springs, that Naruto is coincidentally at as well. There, Yukimaru meets Naruto and they talk about bonds, making Yukimaru glad that there may truly be a place for him. He then leaves a clueless Naruto to wonder who he was.

Trivia

 * Based off appearance, Yūkimaru looks very similar to the Three-Tailed Beast's former Jinchūriki, who was revealed in splash page of chapter 420. They have the same hair and eye colour (purple).
 * Another similarity with to the Three-Tailed Beast's Jinchūriki is their connection to flowers. In the splash page, the Jinchūriki carries a weapon with a flower attached to it, while Yūkimaru first appearance is picking cut flowers.