Imprisonment of Lex Luthor
After the events of the battle with Doomsday, a SWAT team stormed Scout Ship 0344, and subsequently apprehended and imprisoned Lex Luthor into Belle Reve, who had been using the ship's archives to research Steppenwolf.
There, Lex was shaved bald and given his own cell. A number of days later, a guard, accompanied by the warden, ordered Lex Luthor to turn around so that he could come in and restrain Lex, as the warden needed to speak to the prisoner. Instead, Batman appeared, who revealed that he had arranged for Lex to get transferred to Arkham Asylum in Gotham City, as the Dark Knight had "friends" there that could keep an eye on Lex. He responded by giving Batman a threat of the oncoming invasion commanded by Darkseid, and Batman responded by fiercely smashing his branding ring into the wall of the cell behind Lex. When he turned around, the Dark Knight was gone. Lex then promptly ran towards the bars of his cell, yelling out mocking insults at the departing Batman.
Formation of Task Force X
Not long after the death of Superman, Amanda Waller of ARGUS planned to assemble Task Force X, composed of various incarcerated criminals and Metahumans, to serve as her expendable soldiers with exceptional powers, abilities, and skills to defend the world against superhuman threats. Her roster would include the lethal marksman Deadshot, rope assassin Slipknot, boomerang expert Captain Boomerang, monstrous Killer Croc, pyrokinetic El Diablo, and the criminal psychopath Harley Quinn, all of whom were imprisoned at Belle Reve. Waller travelled to Belle Reve with Colonel Rick Flag to inspect her candidates, including witnessing Deadshot's exceptional marksmanship at the Belle Reve shooting range.
After Task Force X successfully defeated Enchantress and Incubus at Midway City, the surviving members of Task Force X were sent back to Belle Reve with reduced prison sentences, and some received special requests, such as Harley Quinn receiving an espresso machine, Killer Croc receiving a television set with cable access, and Deadshot is allowed supervised visits with his daughter Zoe Lawton. However, Belle Reve was later infiltrated by the Joker and his goons and broke Harley Quinn out of jail.
- Lex Luthor - Imprisoned for orchestrating the US Capitol bombing (killing numerous people), and unleashing Doomsday, with the latter nearly bringing about an apocalypse, and resulting in the death of Superman. However, Lex was transferred from Belle Reve to Arkham Asylum, through the influence of Batman since Lex was declared insane and "unfit" for trial. Afterwhich, Lex escaped from Arkham.
- Digger Harkness † - Was to serve 3 life sentences for his 98 cases of burglary (with him having robbed every bank in Australia at least twice). In 2020, a poster of him was shown in the Gotham City Police Department, implying that he might've been on the run again. Regardless, he was back in Belle Reve in 2021. Killed while carrying out his Task Force X mission in the field.
- Chato Santana † - Committed to Belle Reve after killing multiple other inmates at a normal federal prison. Killed while carrying out his Task Force X mission in the field.
- Richard Hertz † - After betraying Task Force X, Blackguard was shot in the face and killed.
- Mongal † - Imprisoned for war crimes and other atrocities. Killed while carrying out her Task Force X mission in the field.
- Brian Durlin † - Savant's neck-implanted nano-bomb was activated during a Task Force X mission in Corto Maltese.
- Gunter Braun † - Javelin never returned to his Belle Reve cell after being killed during a Task Force X mission.
- Cory Pitzner - Left for dead on a Corto Maltese beach, T.D.K. no longer resides in Belle Reve.
- Weasel - Committed to Belle Reve after killing twenty-seven children. Presumed dead after apparently drowning while carrying out his Task Force X mission in the field, but actually survived.
- Abner Krill † - Killed by Starro in Valle Del Mar.
- Robert DuBois - Imprisoned for attempting to kill Superman with a kryptonite bullet. Blackmailed Amanda Waller for his freedom and that of his remaining Task Force X members.
- Harleen Quinzel - Imprisoned for her numerous crimes committed with the help of her ex-boyfriend Joker. However, Harley was later freed by the Joker, who she thought was killed. Imprisoned again for road rage in a bank. Bloodsport then blackmailed Amanda Waller for his freedom and hers.
- Nanaue - Once locked away in prison, King Shark was freed from Belle Reve when Bloodsport blackmailed Amanda Waller.
- Cleo Cazo - Imprisoned for armed bank robbery and using rats as weapons. Bloodsport then blackmailed Amanda Waller for his freedom and hers.
- Belle Reve is a broken version of French for "sweet dreams".
- Belle Reve is based on the DuBois Plantation from A Streetcar Named Desire by Tennessee Williams.
- Belle Reve's location was known only to Amanda Waller and her staff until Harley Quinn's breakout via the Joker, and now both know where it is.
- In a deleted scene from the The Suicide Squad, Cleo is looking for a missing Nanaue, so she leaves Abner Krill with Milton and order him to keep an eye on Thinker. Trying intimidate him, Thinker reveals the reason why Krill is in Belle Reve: her mother was intentionally killed by Polka-Dot-Man, yet Abner says he thought she was gonna hurt him.