The key events in Kakashi's back story start with his father's misfortune. Sakumo Hatake's death left Kakashi with a sense of duty and the need to be a perfect ninja. Then, the mission where he, Obito and Rin were involved. Obito's sacrifice and Kakashi's gain of the Sharingan. His time in ANBU, which exposed him to the darker side of the ninja world. And later, his role as a mentor to the new generation of ninjas, like Naruto, Sasuke and Sakura.
In Kakashi's back story, first is his father's sad end. His father's choice to save comrades over the mission led to disgrace and suicide. This influenced Kakashi's view of the ninja world. Next, the fateful mission with Obito and Rin. Here, Obito's heroic act of saving Kakashi changed everything. Kakashi got the Sharingan and a new sense of purpose. His time in ANBU was filled with dangerous and secretive tasks. After that, his emergence as a teacher for the young ninjas, guiding them with his own hard - earned wisdom and experiences.
Well, one main event is his relationship with his father. His father was shamed for choosing to save his comrades over a mission. This had a big impact on Kakashi. Another important part is his time with Obito and Rin. Obito's 'death' was a turning point for Kakashi, and he got his Sharingan from Obito then.
The death of his father was a significant event that shaped his early life. Also, his participation in the Fourth Shinobi World War was crucial. And his relationship with his students, like Naruto's growth under his tutelage, was important in his story.
Well, first, Kakashi and Rin had a bond during their ninja training days. As they got involved in missions, danger lurked. Rin was kidnapped by the enemy. When Kakashi found her, the situation was already out of control. Rin chose to sacrifice herself rather than be a threat to Kakashi and their village. This series of events is what makes up the sad Kakashi love story.
Kakashi's back story is gradually revealed throughout the Naruto series. You'll get to know more about his past as the story progresses.
The main event is the conflict within his military unit. Another is his presumed death. And then his re - emergence as Soldier 76.
One main event was his rise as a senator on Naboo. Another was his secret Sith training. Also, his manipulation of the Clone Wars was important.
One key event was his father's death. It made him grow up quickly. Another was getting the Sharingan from Obito during a battle. His time in the Anbu was also crucial as it shaped his character. And of course, becoming a teacher to Team 7 was a significant part of his life.
The episodes that focus on Kakashi's back story are mainly in the arc where his past is explored. But it's a bit hard to pinpoint specific ones exactly.
I'm not entirely sure of all the main events in Sakura's back story, but it might involve her first battle where she proved her worth. Maybe she had to defend her village or her lord from invaders.
The main event is the destruction of Flevance. That's where Law lost his family. Then there's the moment he ate the Ope - Ope no Mi. These two things are crucial in his back story.