In "Obi-Wan Kenobi," the Disney+ series, Obi-Wan Kenobi confronts Darth Vader and tells him, "You didn't kill Anakin Skywalker. I did." This line encapsulates Obi-Wan's belief that Anakin Skywalker, the man who was once his friend, was lost to the Dark Side and is now Darth Vader. The duel on Mustafar is a defining moment in their relationship, as it represents the final break between the two.
If you're looking for a specific mention of "Prime" and his children, it seems there may be some confusion, as "Prime" typically doesn't relate to the Star Wars narrative involving Obi-Wan and Vader. Could you clarify what you mean by "Prime and his children"?