As well as Spike, who sacrificed himself in the show's finale, and Angel, who went on to have his own spin-off series, Whedon has hinted that he may be bringing back other characters from the series.
He told Moviehole: "I'm talking in reference to that... and possibly more. I can only teasingly hint, unfortunately, until it's got backing and we've got a schedule and a contract."
Whedon added that he has "been talking to some of the actors, writers, and some executives and are trying to put something together - - but it's not happening fast. I haven't left the Buffyverse behind."