Well after the season 10 promo from Comic con we saw John Glover AKA Lional Luthor so we havelready got hints about that but now we have confirmation:
Entertainment Weekly’s Michael Ausiello today has posted news about another character from Smallville’s past who will be making a comeback in Season 10.
Ausiello has revealed that John Glover, who played Lionel Luthor in the show’s first seven seasons, has signed on to reprise the role for at least two episodes starting in November.
So after hearing that Johnathon Kent is returning from the dead and now Lional, we shall have to see how these decieced characters are back making an appearance, Time travel maybe?>/p<