Let's just say that Sephiroth is demented and evil and wants what is right for him. He believes that he was born from an alien (that crashed into the planet) known as Jenova and that his soul purpose of living was to take over the planet and rule everyone there. He was actually born from a woman named Lucrecia and his father is the scientist Professor Hojo. When Sephiroth was born, he was injected with Jenova cells and plenty of Mako to make a person insane (hmmmm? how ironic). As he grew older he was taken by Shinra Inc. and made him the best of the best. He was actually the best soldier that Shinra ever had. Sephiroth was taken from his mother as a child so he never knew his real mother. What Sephiroth actually wanted was for someone to love him, but no one gave him that love. He was only brought up to destroy.