Star Wars Rebels producers Dave Filoni and Simon Kinberg have confirmed that Darth Vader will have a much bigger role in the second series.
The ultimate villain make a big appearance at the end of the first season and speaking at yesterday's (Saturday April 18) special Star Wars Rebel panel as part of Star Wars Celebration 2015, Filoni confirmed some of their plans.
According to Digital Spy he said that he had spoken about Vader and about Clone Wars character Ahsoka Tano with George Lucas: "I said, 'what would [that battle] be like? What does she know?'
"Let's just say that it's part of the story that we have to tell you."
However despite the appearances of Darth Vader and Ahsoka Filoni said that he wants to seperate Star Wars Rebels from Clone Wars.
He said: "What was really important, and Simon and I discussed this, is that we wanted the cast of Rebels to have their [own] space.
"It's really the story of this crew [and] Ezra's evolution into a Jedi knight. If we found a way to include characters from the past, then those character moments are important [to] the story that we're telling now.
"I think we have to be very careful about which characters we bring into Rebels' period. That includes the classic trilogy and the prequel trilogy as well.
"You worry about having this small universe. Even when we think we're being good at it, we had Yoda, Lando and Tarkin not long after that. I think it played off well, but we have to be conscious so it doesn't seem like a stream of guest appearances."
