“Adam [came] to Krypton with a very specific message to Seg—Superman’s very existence is under threat, and we have to stop Brainiac,” said Welsh. “But we all know Brainiac was always coming to take Kandor City; that’s what Adam Strange got wrong.”
That is to say, Brainiac isn’t any more of a threat to the planet than he was before the show’s story began. Instead, it’s Zod who is trying to alter Krypton’s history. “But not to destroy Krypton; to save it,” said Welsh.
According to the showrunner, the conflict that emerges shapes the second half of the season. For instance, when Adam Strange realizes he was wrong, and that Zod is seeking to alter the future, Strange tries to convince Seg that history needs to play out according to plan, and his planet needs to die. If Krypton survives, Kal-El would never become Superman and save the universe from countless threats.
“If you extrapolate that, it means allowing Kandor City to be taken to ensure Superman’s birth,” said Welsh. More importantly, the reveal marks a “big moment” in Seg’s hero’s journey, because Zod and Adam will both be “vying for his soul.”