Special Guest Stars Stephen Amell voices Oliver Queen / Green Arrow Grant Gustin as Barry Allen / The Flash Melissa Benoist as Supergirl / Kara Zor-El / Kara Danvers Danielle Panabaker as Caitlin Snow David Ramsey as John Diggle / Spartan Rick Gonzalez as Rene Ramirez / Wild Dog Chyler Leigh as Alex Danvers Juliana Harkavy as Dinah Drake / Black Canary Elizabeth Tulloch as Lois Lane Jon Cryer as Lex Luthor Tyler Hoechlin as Clark Kent / Superman Ruby Rose as Kate Kane / Batwoman Tom Cavanagh as Dr. Harrison Nash Wells Nicole Amber Maines as Nia Nal / Dreamer Cress Williams as Jefferson Pierce / Black Lightning David Harewood as J'onn J'onzz Marv Wolfman as Autograph Seeker Marv Guest Stars Reina Hardesty as Joss Mardon / Weather Witch Audrey Marie Anderson as Lyla Michaels Osric Chau as Ryan Choi Eileen Pedde as The President Co Starring Jorden Birch as Worker Tiahra Allen as Baby Sara Diggle Raul Herrera as Sargon Marcello Guedes as JJ Diggle Pam Kearns as Female Fan Credit Only Matt Ryan as John Constantine
