Rin Nohara

Rin, a medical ninja, was the teammate of Hatake Kakashi and Uchiha Obito during the Kakashi Gaiden arc. She is a sweet and friendly girl who cares for her teammates. She is also the one who implanted Obito's left eye into Kakashi, giving him his Sharingan. She has intimate feelings for Kakashi. It's revealed that she's dead, stated when Kakashi is killed by Pain. This death of Rin was the start of conflict within Obito. Kakashi apologizes to Obito because he broke their promise and failed to protect Rin. It's later revealed that it was Kakashi who killed Rin with his Raikiri. Albeit that Rin deliberately jumped in front of it.