There are NO plans to have me return to SPN at ANY juncture. Of course, one also needs to remember that Sheppard has been firmly vocal about not having any intention to return to the show. Therefore, it still seems unlikely that Mark Sheppard would agree to return for the finale of 'Supernatural' Season 15.

Does Crowley come back in Supernatural?

In an exclusive interview with Michael Ausiello on July 15, 2010, series creator Eric Kripke confirmed that Crowley would return in the show's sixth season.

Does Ketch come back in Supernatural Season 15?

Ketch returned in season 15's second installment, helping the Winchesters fight back against the souls of Hell, but getting possessed by none other than Jack the Ripper. ... While Ketch was recovering, however, he was attacked and killed by Ardat with little to no fanfare.