Guest Stars John Kavanagh as The Seer Nathan O'Toole as Bjorn Lothbrok Co Starring Maude Hirst as Helga Jefferson Hall as Torstein Tadhg Murphy as Arne Elinor Crawley as Thyri Haraldson Ruby O'Leary as Gyda Lothbrok Diarmaid Murtagh as Leif Steve Wilson as Horik's Companion Damien Devaney as Priest 1 Niall Ó Sioradáin as Priest Uppsala Paul Ward as Priest 2 Rudi Kennedy as Young Man