Special Guest Stars Stephen Amell as Oliver Queen / Green Arrow Grant Gustin as Barry Allen / The Flash Emily Bett Rickards as Felicity Smoak Melissa Benoist as Supergirl / Kara Zor-El / Kara Danvers Danielle Panabaker as Caitlin Snow David Ramsey as John Diggle / Spartan Carlos Valdés as Cisco Ramon Guest Stars Christina Brucato as Lily Stein Lucia Walters as President Susan Brayden Donnelly Rhodes as Agent Smith Co Starring Jacob Richter as Young Agent Smith
