|“||I still remember the first moment we met. Mmm. There was nothing, just darkness and... then she appeared. It did not take long for us to light up the universe.||„|
|— God Johnson to Lucifer|
in "God Johnson"
The universe is a physical realm created by God and Goddess long ago. According to Lucifer, when two Celestial Beings fell in love and had sex, it caused the creation of the universe, i.e. "the Big Bang".
Prior to "The Good, the Bad and the Crispy" there was only one known universe, and everything that existed was contained within. Lucifer used the Flaming Sword to cut a tear in the fabric of the universe for Goddess to leave through, to create her own universe. After Goddess passed through, Lucifer threw two pieces of the Flaming Sword through, forever separating the two universes.
Later in "Once Upon a Time", God created an alternate universe that was an exact copy of the original until the day John Decker was supposed to die. With Decker saved, subsequent events play out differently. For example, in this universe, Lucifer and Chloe don't meet the night of Delilah's murder.
However there exists many universes in the Multiverse, and Lucifer's Universe is known as Earth-666, prior the relationships between Lucifer and Chloe, John Constantine, Mia Smoak and John Diggle who were Inhabitants of Earth-1, traveled briefly to Earth-666, asking Lucifer for help, and he gave them a devil card to find Oliver Queen's soul in the Purgatory.
In "Nothing Lasts Forever", God chooses to depart the Universe to retire with Goddess in her new universe.
- This universe is part of the Arrowverse, as revealed in the third part of the Crisis on Infinite Earths crossover event. It is designated as Earth-666.
- Additionally, it's revealed God only created the first version of Earth-666 in the multiverse. The version that appears as of Season 1 was created by Oliver Queen/The Spectre and the seven Paragons at the dawn of time.
- Maze is the only demon to get a second life, as she was not in hell (a plane of existence not affected by anti-matter).
- After the multiverse reboot, Lucifer's history from City of Angels? was altered. As it was not possible for John Constantine to visit, Lucifer brought Maze himself. He also brought various memorabilia from his previous visits (like an autographed copy of Hamlet and a horse bust from Napoleon).