1 year ago
Last edited at 12:02PM on 12/10/2012
It was implanted to him by Rin one of the team members on the mission during the great ninja war led by the guy who'd eventually be the fourth hokage(Minato Namikaze). Obito Uchiha was crushed under a rock after a hidden stone ninja(jounin) went after them. Half of his body was crushed. As a parting gift to Kakashi partly because of him being promoted to Jounin. His good left eye was transefered to Kakashi. Given that he does not have pure Uchiha blood running in his veins. He consumes a lot more chakra to use "his" sharingan.
Kakashi has the sharingan eye because when he was on a mission with Obito and Rin they were attacked by enemy shinobi, Obito, who was a uchiha then awakened the sharingan protecting Kakashi and Rin from a falling rubble. Obito was in half and about to die, but he never gave Kakashi a present for graduating to Jounin, therefore he knew he was going to die so he had Rin implant his Sharingan eye into Kakashi.