Based on the context and the answer, generate a question. 

Context: His heart grew weary at the thought . It was a new reaction to a painful memory . Vader wondered if this was how Obi - Wan had felt when they fought on Mustafar . Anakin promptly buried the thought as he took control of the battle ; he did n't really want to know .

Answer:

Friend



Who might Obi - Wan be to him ?