Yashamaru

was a medic-nin, the younger brother of Karura, and thus the uncle of Gaara.

Background
At first, Gaara thought that he was the only one that cared about him. Yashamaru taught Gaara about physical pain, emotional pain and love; concepts Gaara was completely unaware of in his childhood. He was commanded by the Fourth Kazekage to assassinate Gaara, but was given the choice in deciding whether he wanted to proceed or not. Yashamaru willingly accepted the command in order to avenge his older sister's premature death. The assassination attempt, however, ended in a desperate suicide mission and ultimately failed. Before he died, he told Gaara that no one had ever really loved him, not even him. This left Gaara even more of an emotional wreck than he already was. His suicide bombing attempt on Gaara's life caused Gaara to become somewhat psychotic. Yashamaru's last words, to Gaara, were "This is it. Please die."

Trivia

 * In the Polish and Italian versions of the Naruto manga, Yashamaru is portrayed as female rather than male. Even in the English version, we are never given full confirmation that Yashamaru is male, which gives rise to the belief that Yashamaru could be a woman.
 * Yashamaru's name, 夜叉丸, is composed of three Kanji. The first two, Yasha (夜叉) refer to creatures in Japanese mythology known as "Night Demons" (See Yaksha ). The Hindu version of the Yakshas usually portray them as having two sides: a darker, more sinister side, and a benevolent, lovable side. Yashamaru's betrayal could be a reference to this "dark side" of Yakshas. Maru (丸) is a common ending for male names.