After the death of New 52 Superman in "The Final Days of Superman," DC has replaced him with the pre-Flashpoint Superman under its Rebirth franchise. Hence, the red-caped hero from "Superman: Rebirth" will be one of the new members of Justice League in "Justice League: Rebirth #1."
Similar to the aftermath in the "Crisis on Infinite Earths" timeline, the current Superman was reluctant to join the League. However, after much persuasion by his wife, Lois Lane, he finally decided to become a member.
Superman will be joining the other two new members of the League, both of whom happen to be Green Lanterns — Simon Baz and Jessica Cruz. As Hal Jordan has exited the team and the New 52 Superman is dead, the trio will play a pivotal role in forming the latest version of the League along with Wonder Woman, The Flash, Aquaman, Cyborg, and Batman.
Usually, Batman doesn't trust any new members easily, not even if the member is someone like Superman. However, it seems that the Dark Knight has his full trust in the new Superman, for reasons unknown. There might be a possibility that Batman is keeping an eye on his activities to find out his true identity.
Besides introducing the new Superman, the issue will also see the debut of The Reapers; an alien race that is very similar to Justice League's earliest foe, Starro the Conqueror. Starro was a giant purple-coloured starfish who had psychic powers to control humanity. The Reapers also possess similar powers, but instead of looking like starfish, they appear as giant cockroaches with long tentacles.
"Justice League: Rebirth #1" is written by Bryan Hitch and the illustrations are done by artist Tony Daniel. Tony will be accompanied by Jesus Merino for the later issues of the series, as reported by Comic Book.