Hatake Kakashi is one of the very few members who posses the Sharingan after Uchiha Itachi eliminated the Uchiha clan .
But, how did Kakashi get the Sharingan, even though he is not from the Uchiha clan? Wanna know that? Let me tell you the story-
Sakumo Hatake, Kakashi’s father was a kage level shinobi from Konoha. Sakumo and his teammates were once sent on a mission that meant a great deal to Konoha. While on the mission, he was left in a position where he had only two options, to complete the mission or save his comrades.
He was in a fix, but chose the latter avoiding the mission. As the mission was a failure, the Fire country suffered huge losses.
Everyone in the village started blaming Sakumo for this, what’s more? The people whom he had saved also started blaming him. Unable to bear the pain, he went in to depression and committed suicide