"If I've been reading (and re-reading, and re-re-reading...) my sons' D.C. Comics Encyclopedia correctly every night at bedtime, this should be one very neat trick. With Lex Luthor quietly exiting stage right, no less than Doomsday is coming to Smallville.
Though the CW's official announcement dare not actually utter the big guy's alias, Sam Witwer — whom Battlestar Galactica fans may remember as Alex "Crashdown" Quartararo — will fill the role of Davis Bloome.Doomsday, of course, is the baddie who according to canon one day will kill Superman. On Smallville, though, he'll start out as just a charismatic paramedic... though one with a deep-seeded dark side. (No, I didn't say Darkseid.)In addition, lest Lex's affairs go untended in his absence, nubile newcomer Cassidy Freeman is also joining the 'Ville as Tess Mercer. Her name an obvious nod to "Miss Tessmacher!", this spunky gal is the acting CEO of Luthorcorp — and she boasts a cunning ruthlessness to match her mentor's." — Matt Mitovich
Source: TV Guide