He found a child that the rebels were trying to kill. They feared that they're gonna be raised by Darth Vader.

Vader saved this innocent child. He decided to take responsibility for this child's future.

He trained them for many years, teaching them the secrets of the Force. As the child grew, the bond between them grew. When it was older, they we're still loyal to him, which made him..happy.

"How was the mission?" His modulated voice echoing through the halls of the Death Star.