|Season 4, Episode 20 (82)|
|Krypton's Last Stand||The Devil Within|
PART 3 OF 3: THE END OF A WORLD- Kara Danvers, Clark Kent, Dru-Zod, and Ursa are transported to the final days of Krypton, where they are given a choice: save their home-world and irrevocably alter their fates or let it die and live with their inaction. On Earth, Alex Danvers and James Olsen stave off the remaining Kryptonians under Bertron's command.
- Melissa Benoist as Kara Danvers/Supergirl
- Chyler Leigh as Alex Danvers
- Jeremy Jordan as Winslow Schott
- Katie McGrath as Lena Luthor
- Laura Benanti as Alura Zor-El & Astra In-Ze
- Zachary Quinto as General Dru-Zod
- Tyler Hoechlin as Clark Kent/Superman
- Odette Annable as Reign
- Jenna Dewan as Lucy Lane/Superwoman
- with Claire Holt as Karen Starr/Power Girl
- and Mehcad Brooks as James Olsen/Guardian
Special Guest StarsEdit
- Jon Cryer as Lex Luthor
- Sarah Shahi as Ursa
- Michael Rosenbaum as Lex Luthor (Earth-30)
- and Jason Momoa as Lobo
- Amy Acker as Brainiac
- James Marsters as Bertron
- Rachel Brosnahan as Kate Kane
- Emmanuelle Chriqui as Sarah Essen
- Rachel Nichols as Slam Bradley
- Elizabeth Tulloch as Lois Lane
- Minka Kelly as Dawn Granger
- Brenda Strong as Lillian Luthor
- Wallis Day as Nyssa-Vex
- with Katheryn Winnick as D.I.S.C.O.R.D.
- and Dianna Agron as Major Raya Zod-El
- and Alexandra Daddario as Cameron Chase
- Antagonists: Bertron, Reign, Dru-Zod, Ursa, Brainiac, D.I.S.C.O.R.D.
- Alura was last seen in City On Fire, while Astra was last seen in Under The Blood Red Sun. They appear only in the Krypton segments of the episode.
- This is the 4th season finale to feature Kara, Alex, James, and Clark.
- This is the 3rd season finale to feature Alura, Lucy, Lena, Reign, and Eliza.
- This is the 2nd season finale to feature Astra, Karen, Zod, Brainiac, Sam, Ruby, Winslow, Imra, and Lois.
- This episode takes place on July 29-30, 2020.