PhanTresh
After Minato and Kushina's death, Kakashi was in charge of taking care of their child, Naruto. He got help from Rin and Obito, and mostly had Obito spend nights with him, to help him out, but also for personal reasons besides Naruto. But one day, Obito nor Rin return his calls. He then walks to Obito's apartment, which was surprisingly opened. He has to make a hard decision, does he make the right one? He'll never know, but it'll scar him for life. Naruto and Kakashi got separated in order to protect Naruto from danger, when Naruto was only 12. Kakashi's life was devoted to protecting Naruto, and he'd stop at no cost in order to fulfill his duty.