Peacemaker Season 2 made the ending of Superman significantly better, which is a great sign for the future of the DCU. When James Gunn and Peter Safran began developing Chapter 1 of the DCU (which is officially called Gods and Monsters), they promised an interconnected franchise similar to the MCU where different projects would have implications on future, and, in some cases, even past, projects. Now that the DCU is completely underway, that promise is already being fulfilled.
At the end of Superman, just after the Man of Steel takes down Lex Luthor, the camera cuts to show Frank Grillo's Rick Flag Sr., and, during the scene, General Mori tells Rick, "Glad you're not concerned about the metahumans, Rick. "Cause now they're the ones making the rules." However, that seems to obviously not be the case anymore after his actions at the end of Peacemaker Season 2.
Throughout Season 2, fans were able to see Rick spiral further and further out of control. He was still grieving the death of his son, Rick Flag Jr., but it only made things worse when he found out in Season 2, Episode 2 that Peacemaker was the one who killed him. His grief, then coupled with rage, led him to become more and more hostile, until he eventually formed a necessary partnership with none other than Lex Luthor.
Lex made it abundantly clear in Superman that he despises metahumans and prefers them all to be gone. Rick does not necessarily share that same sentiment, and James Gunn has confirmed previously that Rick doesn't hate metahumans, but the two clearly formed a shared goal in Peacemaker Season 2 due to how the installment ended.
Fans who watched Peacemaker Season 2 will remember that Lex and Rick met face-to-face. It was a giant cameo for the series that clearly led to other plot points later in Peacemaker, such as what is known as Salvation.
After meeting with each other, Lex and Rick essentially came up with an interdimensional prison known as Salvation, thanks to the Multiverse and the portal that Lex helped Rick with. In the Season 2 finale, Rick received a note from Lex. For reference, this prison is meant to contain metahumans, and it will be extremely important to the future of the DCU.
The note specifically said, "Rick, looks promising! Can't wait to see what's next." Lex then signed his name. This confirmed that Lex and Rick were working on Salvation together, which further teased the future of the DCU. Lex will play a major role in Man of Tomorrow, the Superman sequel, so it is possible that any updates on Salvation will be featured in that movie.
When looking back at the ending of Superman, the final scene for each character in that film now has more meaning because of what occurred in Peacemaker. Lex was clearly upset after his arrest, and he hadn't solved anything regarding metahumans. In fact, because of everyone in his interdimensional prison being freed and the heroes discovering the prison, everything pretty much backfired on him.
However, because of Peacemaker, he is now able to be in a facility with no metahumans instead of being in Belle Reve, and his partnership with Rick brings him one step closer to achieving his ultimate goal of ridding the world of metahumans.
It is also poetic when looking at Rick's final scene because the last line of dialogue spoken to Rick was about him not being worried about the metahumans. Now, at the end of Peacemaker, he has found a place to imprison metahumans so that they are not even present on Earth.
How Rick Flag's Character Arc Has Carried Over From Creature Commandos
Rick Flag played an important role in Superman and Peacemaker Season 2, but his character arc really started in Creature Commandos. That series introduced the grief-stricken version of Rick and planted the seeds that have now sprouted across multiple appearances.
For example, Rick joining the Creature Commandos gave him somewhat of a purpose after mourning the death of his son. Being a part of the team and leading them showed him what he was still capable of and brought some of his confidence back.
However, it also made him more susceptible to manipulation. Due to the romantic bond he formed with Ilana Rostovic and the injury he sustained, he became more mentally unstable. At the end of the day, Rick Flag changed. After the events of Superman and now Peacemaker Season 2, Rick is more dangerous than ever, both to others and to himself.
