Yūkimaru

is a young boy (it is still unknown if he is a shinobi) who appears in the second Naruto Shippūden filler arc. He seems to be another test subject of Orochimaru.

Hunt for the Three-Tails Arc
So far we have only seen him once in this arc, collecting tree flowers after Sasuke Uchiha cut them off with his Chidori for his training.

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.
 * Another similarity with to the Three-Tailed Beasts 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.