Special Guest Stars Emily Bett Rickards as Felicity Smoak Willa Holland as Thea Queen Paul Blackthorne as Detective Quentin Lance Echo Kellum as Curtis Holt Colton Haynes as Roy Harper Katie Cassidy as Laurel Lance (Earth Two) / Black Siren Susanna Thompson as Moira Queen Caity Lotz as Sara Lance Colin Donnell as Tommy Merlyn Grant Gustin as Barry Allen Sea Shimooka as Emiko Queen Melissa Benoist as Supergirl Guest Stars Audrey Marie Anderson as Lyla Michaels David Nykl as Anatoly Knyazev Katrina Law as Nyssa al Ghul Joe Dinicol as Rory Regan Lexa Doig as Talia al Ghul Co Starring Keri Adams as Bethany Snow Jack Moore as William Clayton Marcello Guedes as John Jr. Jessica Heafey as Documentarian / Marcia Pedowitz Tiahra Allen as Young Sara Diggle Johnny Cuthbert as John Byrne
