A/N: I love Kakashi. His past makes me sad (like about ¾ of all Naruto members do), and this is somewhat based upon an observation of mine.
EDIT: A few reviews pointed out a mistake I made about the timeline, and I've finally fixed it. ; Thanks so much for pointing it out to me.
Disc: Masashi Kishimoto owns Naruto, not me.
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Hatake Kakashi was used to losing things. Or, more specifically, people.
The first person he lost was his mother, who died when he was two. It hadn't really hurt; after all, how could you miss what you never knew? Of course, he wished he still had a mother, especially when he saw all the other children and their mothers, but it was nothing more than a dull ache. He was okay.
The second person he lost was his father. He had beenseven, and had just become a chuunin two months beforehand. He had gone home from his training session early, and it was a beautiful, sunny day. Not a single cloud was to be seen. But all the blue had turned to red when Kakashi stepped into his home. He remembered the sword that was stuck in his father's body, which was slumped over on the floor in a pool of blood. Kakashi had known about the failed mission, and all the hateful stares and accusing words, but he had thought that his father would try to get through it, for his sake. He had thought wrong.
And then there was Uchiha Obito, his rival, teammate, and friend. Kakashi blamed himself for Obito's death, no matter what his sensei or Rin had tried to tell him. If Kakashi had moved at the right time, if he'd stayed alert during the rockslide, if he hadn't let Rin get kidnapped in the first place, then he knew that Obito would still be here. The reason Kakashi kept his sharingan covered was that he could not stand to see it, and that he didn't want anyone else to see it either. It was a constant reminder of how he'd screwed up and watched his teammate die right in front of him. It was a reminder of how he'd failed his first day as a jounin. Kakashi hated being reminded of his failures.
Rin had died only 8 months later, although Kakashi was fortunate enough to have not witnessed her death. She had been acting as a medic-nin on the field, healing Fire Country's wounded shinobi. She'd apparently met her end by the hand of a patient she'd tried to save; he had been an enemy masquerading as a Leaf nin, and when she'd had her back turned…Kakashi knew the rest. Her body had at least been brought back to the village for a proper burial; Obito hadn't had that mercy. Kakashi knew all about Rin's feelings for him, and couldn't stop wondering what could have happened between them if she hadn't died.
And, perhaps the most painful next to his father's, was his sensei's death. The Yondaime Hokage, the Yellow Flash of Konoha, the closest thing to a father that Kakashi had had since the death of his real one. He had died protecting the village he loved so much, a death that fit him well. But Kakashi couldn't forget the promise that Yondaime had made him, after Kakashi had discovered his father's body. It was a promise that he'd repeated to the silver haired jounin after the deaths of Rin and Obito as well; the promise that he would never leave him. Of course, Kakashi knew that it was selfish to be upset over a broken promise, since it paled in comparison to his sensei's promise to protect Konoha, but he couldn't help it. He had thought, he had hoped, that there would at least be someone in his life that didn't have to leave him. And of course, fate had to ruin those hopes.
After Yondaime died, Kakashi devoted himself completely to his training. He soon became one of the best jounin in the Hidden Leaf Village, and after he had joined the ANBU, he became even more widely known. For the longest time, he refused to have a genin team; many thought that he was simply too busy for it. Truthfully, though, he had just been too afraid to get close to anyone. He didn't want to go through the pain of losing anyone again.
This had changed when he met Sakura, Sasuke, and Naruto, however. He'd finally decided to take them on as his genin team; he thought that it would end up being okay. They reminded him of how his team had been, although Sasuke was the one that reminded him of himself. Because of this, Kakashi took special care of the Uchiha, looking out for him a little more than his other two students. Ironically enough, Sasuke was the first to leave, abandoning Konoha to go train under Orochimaru. Then Naruto had gone off to train with Jiraiya for two years, and Tsunade had taken on Sakura as her apprentice. Kakashi almost found it funny that each of his three students were now being trained by the three legendary sannin. But usually it hurt him too much for it to be funny.
Many now thought that Kakashi had chosen to become aloof because he was naturally the kind of man to do so. Many women were disappointed that Kakashi refused to date them, but it also served to make them even more interested in the infamous Copy-nin, since all women loved the quiet, mysterious type. Kakashi sometimes wondered with a bitter smile what they would say if they knew that he spent every morning talking to people who had long since died. But really, it was safest for him that he only converse with the spirits.
After all, you can't lose what you've already lost.