You and Kakashi were siblings, however you injured yourself back when you were little so it left Kakashi to care for you, a pretty big injury that caused you to retire from being a ninja (you can pick your injury). You lived in the forest away from everyone, only surrounded by forest, making it almost impossible for anyone to find you, except Kakashi of course. After a few years, he gained a few students; Naruto, Sasuke, and Sakura. You got to meet them for the first time.

“I’m back,”