Warning: SPOILERS for Superman & Lois season 1, episode 10, "O Mother, Where Art Thou?"
The Arrowverse has unveiled Morgan Edge's real identity in Superman & Lois season 1 as Kal-El's brother, while adding a new twist to the DC mythology. Superman & Lois has so far had a lot of twists and turns in its first season. One of the most prominent examples was the revelation that Captain Luthor was actually John Henry Irons, a.k.a. the DC Comics superhero Steel. However, Superman & Lois had another major bombshell ready for the viewers with the show's current main antagonist. Episode 9, "Loyal Subjekts," ended with Morgan revealing himself as a fellow Kryptonian while referring to Superman as his brother.
Following a major cliffhanger like that, it naturally sparked massive speculation on which DC character Adam Rayner was actually playing in the Arrowverse. Out of the many Kryptonian villains that exist in Superman's mythology, General Zod, was one of the popular theories. Instead, Superman & Lois exceeded a lot of the expectations by making Morgan an original Kryptonian, but still as Superman's brother. In "O Mother, Where Art Thou?," Morgan introduced himself as Tal-Rho, the son of Zeta-Rho and Lara Van-El, making him and Kal-El half-brothers. Before Lara married Jor-El, she had been genetically matched to Zeta, as Tal was conceived through the Kryptonian birthing matrix, while Clark was born naturally.
Tal came to Earth years before Clark, but while Clark ended up in Smallville and was raised by the Kents, Tal took a page out of the Superman: Red Son story (in which Superman arrived in Russia instead of Smallville) and landed somewhere else. He grew up learning people feared him instead of being loved. That fundamentally altered his perspective of humans and sent him down a different path. Interestingly, while there isn't a Tal-Rho in the comics, there's still precedent for Superman having a brother, especially one who wasn't born like Clark. Kon-El, one of the many Superboys, has had a handful of origin stories, but regardless of how he was created - and from whom - Superman typically considers him to be his brother. But at least in that regard, Superman is the older brother and is the one in charge.
In-universe, though, perhaps the most intriguing aspect is how the Arrowverse's Crisis on Infinite Earths even changed Morgan Edge. The crossover did more than just recast the character; it rewrote his entire existence, taking him away from being a mere businessman to an actual Kryptonian. In doing so, Superman & Lois set up a major twist for fans, along the same lines as the John Henry Irons reveal. Rather than use new characters, or more comic-accurate origins for these comic characters, the series is utilizing the gifts given to it from Crisis on Infinite Earths to do wild things with its story. In many ways, they can keep viewers at the edge of their seats because anyone can be anyone now.
Even though Morgan turned out to be Tal-Rho rather than General Zod, that doesn't mean Superman & Lois can't or won't use him in future seasons. Having Tal be Superman's brother allows this Man of Steel to get a new Kryptonian family story. Since they are related, that means Tal is likely not a one-season Arrowverse character. Even if/when Tal is defeated in Superman & Lois season 1, it is hard to imagine he would never show up again in the Arrowverse in future seasons. Assuming Tal doesn't somehow get killed, it will be intriguing to see where they take Superman's brother throughout the rest of Superman & Lois season 1 and beyond.