Special Guest Stars David Ramsey as John Diggle Stephen Amell as Oliver Queen / Arrow Melissa Benoist as Supergirl / Kara Zor-El / Kara Danvers Brandon Routh as Ray Palmer / The Atom Caity Lotz as Sara Lance / White Canary Cress Williams as Jefferson Pierce / Black Lightning Katherine McNamara as Mia Smoak Elizabeth Tulloch as Lois Lane Tyler Hoechlin as Clark Kent / Superman David Harewood as Hank Henshaw / J'onn J'onzz / Martian Manhunter Tom Ellis as Lucifer Morningstar Jon Cryer as Lex Luthor Ruby Rose as Kate Kane / Batwoman Matt Ryan as John Constantine Brandon Routh as Clark Kent / Superman of Earth-96 Guest Stars Audrey Marie Anderson as Lyla Michaels / Harbinger John Wesley Shipp as Barry Allen / The Flash of Earth-90 Osric Chau as Ryan Choi Wentworth Miller voices Leonard AI Stephen Lobo as Jim Corrigan / The Spectre Ashley Scott as Helena Kyle / Huntress Uncredited Dina Meyer voices Barbara Gordon / Oracle
