Kakashi Hatake, aka the Copy Ninja, is one of the most popular and well-known ninja in history. He is also one of the most enigmatic and mysterious ninja ever to live. Notwithstanding his fame, few know much about Kakashi’s past. Some believe that he was once a member of the Seven Ninja Swordsmen of the Mist, but this is only a theory. What is known for sure is that Kakashi disappeared for a long time after his graduation from the Ninja Academy and returned as an ANBU lieutenant in 699 BBY.
In 606 BBY, he was assigned to lead Team 7, which consisted of himself, Naruto Uzumaki, Sakura Haruno, Sasuke Uchiha, and Itachi Uchiha. In sharp contrast to Naruto and Sasuke who were always fighting and making mischief, Kakashi was always the calm leader and mentor. After Team 7’s disastrous attempt to capture Itachi Uchiha in 506 BBY, Kakashi left the village to train under Jiraiya for two years. After his return in 502 BBY, he served as an ANBU captain under Minato Namikaze until his death in 399 BBY.
What is known for certain is that Kakashi was not present during any of the major events in Naruto’s life. This has led many fans to speculate whether or not Kakashi was actually in the Bingo Book or if he just gave Naruto false memories of being close to him. There are several pieces of evidence that support this theory. The first is that there are no records of Kakashi ever teaching Naruto any jutsus that would have been useful in defeating Madara Uchiha or Obito Uchiha.
The second is that when Naruto finally confronts Kakashi about these memories, Kakashi does not seem surprised or UPSet by them like he would if they were true memories. Finally, there are several hints from both Jiraiya and Tsunade that suggest Kakashi may not have been entirely truthful with Naruto about his past. If Kakashi was really in the Bingo Book then it would make sense that he would be able to remember all of those events because they would have happened directly to him. However, since Kakashi never mentions these memories or seems disturbed by them it seems unlikely that they are real memories.