[Obi-Wan was shocked and mildly offended at this revelation. To think that his image would be used to train a Sith apprentice. But then he supposed it was fitting.]

Darth Vader wasn't always so evil. He was my apprentice. I trained and raised him from a small boy. Except he was taught to be a Jedi, not a Sith.

[It was practically the opposite situation to Starkiller's.]

If someone can be consumed by darkness as he was, then I believe you can learn to use the light as well.