|Season 4, Episode 16|
|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, Maggie 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
- Floriana Lima as Maggie Danvers
- 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)
- with Jason Momoa as Lobo
- and Dean Cain as Jeremiah Danvers (uncredited)
- Amy Acker as Brainiac
- James Marsters as Bertron
- Rachel Brosnahan as Kate Kane
- Emmanuelle Chriqui as Sarah Essen
- Rachel Nichols as Onyx
- Elizabeth Tulloch as Lois Lane
- Minka Kelly as Dawn Granger
- Brenda Strong as Lillian Luthor
- with Katheryn Winnick as D.I.S.C.O.R.D.
- and Dianna Agron as Major Raya Zod-El
- 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, Maggie, 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.