Yūkimaru

is a young orphan boy who appears in the Naruto Shippūden anime. He is a test subject of Orochimaru, because he has the ability to control the Three-Tailed Giant Turtle.

Personality
Yūkimaru is a quiet and a gentle boy, probably due to his past. He constantly asks questions like "Is it going to be fun?". His main goal is to find home and is told by Naruto that home is a place where people think about you, which lightens his spirit.

Hunt for the Three-Tails arc
Kabuto conducts an experiment on Yūkimaru by forcibly releasing his chakra, partially calling forth the Three-Tails. Kabuto is satisfied with the results and takes an exhausted Yūkimaru Yugakure to rest. There, Yūkimaru meets Naruto Uzumaki and they have a brief discussion about bonds. Soon afterwards, he is sent on a mission with Guren but gets sick along the way. Guren takes care of him a and they grow close, Guren reminding him of his mother. Guren gives him a crystal, telling him that it will remain intact for as long as she is alive. Once he gets better he runs into Naruto again, who offers to take Yūkimaru back to Konoha. Yūkimaru politely declines as he feels his place is with Guren.

Later, Kabuto conducts another experiment with Yūkimaru; by giving him more pills he is able to completely summon the Three-Tails. The strain causes his nose to bleed and he soon passes out, causing the beast to go on a rampage. When he wakes up he finds Guren fighting the beast in order to protect him. Yūkimaru uses his remaining strength to keep it away from her, but they are quickly washed away by the Three-Tails.

After recovering from the ordeal, Yūkimaru find Guren and Naruto arguing over him. Yūkimaru tells Naruto he is happy to have met him, because now he has a place to be: with Guren. When Guren engages the Three-Tails again, Yūkimaru restrains it without the aid of Kabuto's pills for a short while. The beast escapes from his control and Yūkimaru passes out. A group of Konoha ninja find and attend to him, and when he comes to he tells them that Guren and Naruto have been eaten by the Three-Tails. Yūkimaru helps them locate the beast and, after finding it, goes to hide with Sai. He is quickly captured by Rinji.

Taking advantage of Yūkimaru's feelings for Guren, Rinji convinces Yūkimaru to take more of Kabuto's special pills and use his powers to control the Three-Tails. He uses all of his strength to bring the Three-Tails to their location, and as he collapses he is caught by Guren. Rinji goes on to inform Yūkimaru of the fact that Guren killed his mother, something Guren does admits to. Yūkimaru is speechless, but Naruto interjects, speaking on behalf of Guren, telling Yūkimaru how much she had changed; while the past Guren committed terrible sins, this Guren was regretful of her past transgressions. Guren adds that, if he would allow it, she would protect him forever. Yūkimaru accepts.

Rinji attacks them, in doing so revealing himself as Kabuto. Kabuto explains what Guren and Yūkimaru's purpose was: for the two of them to get close and become dear to one another, so when Yūkimaru learned of Guren's murder of his mother, he would use his anger to make his power explode, though he is visibly surprised this did not occur. He continues to speak about the violent future ahead for the entirety of the Ninja World--and that being their reason for using Yūkimaru to gain the Three Tails.

While Naruto fights with Kabuto, Guren and Yūkimaru flee. Kabuto sends Rinji's animated corpse after them, so Guren defends Yūkimaru. When her Crystal Release attacks prove futile against Rinji's bats, Guren encases herself and Rinji in crystal and they fall into the lake. Believing Guren to be dead, Yūkimaru lets loose his power, driving the Three-Tails into a frenzy, and shattering the seal the Konoha ninja were very close to completing. Once the beast is driven off, Naruto finds Yūkimaru and brings him back tot he other Konoha ninja to rest. While there they discover that his body had not been able to handle the strain and he had lost his ability to control the Three-Tails.

Yūkimaru awakens to find the crystal Guren had given him fully repaired and glowing. He rushes off into the night to find her. Naruto, after realizing he is gone, goes to search for him--but when he finds Guren's crystal left in a patch of bushes unblemished, he knows where Yūkimaru has gone, and decides to let him be. He makes this point to the rest of the Konoha ninja the following morning, deterring them from searching for Yūkimaru. As the Konoha ninja are leaving, Yūkimaru, alongside Guren and Gozu, look down upon them; and Naruto sees them walk away. Yūkimaru's hand is seen holding Guren's, as they walk into the distance.

Trivia

 * Because of his connection to the Three-Tails, Yūkimaru is believed to have some connection with its former jinchūriki: Yagura. They have similar appearances and both have an apparent connection to flowers.
 * Yamato refers to Yūkimaru's mysterious usefulness to Orochimaru as "the ability to synergize with a Tailed Beast."
 * Yukimaru's favorite flowers are white camellias.

Quotes

 * "I like red camellias. I like white camellias.  Camellias drop the entire flower, not just their petals.  You can remove the oil from the flower, and the tree itself can be used to make ink."
 * (To Guren) You're a nice person Guren... You are the one I should return to, after all... and I'm the one you should return to, Guren. 
 * (To Guren) Uh-huh...And I will always think of you Guren. For now and forever... and ever...I love you.