A new fan theory concerning the revelations in "Lucifer" Season 5 involves Chloe Decker's purpose in the Devil's life, and that is supposedly to make him stay on earth.
Reddit user Henlioc has this theory that God placed Chloe (Lauren German) in Lucifer's life because he wanted his son to be happy. He claimed that God was no longer punishing Lucifer and that was why he brought Chloe to him. She is the reason why he can stay on earth and not go back to hell.
"[Spoiler] So, he was so mad at God for putting Chloe in his life, basically creating her so they would meet. She's the reason he stays in LA for a while," the Lucifan wrote, adding, "But Lucifer keeps thinking that God wants him back in hell. But God knew Chloe would keep Lucifer on Earth."
"So....has anyone else thought that God was actually okay with Lucifer staying on Earth, that his punishment was over and God wanted Lucifer to find love and happiness?" the user continued.
Lucifer does not know that Chloe is a miracle child. God gave her to a couple who could not bear a child. He sent Amenadiel to bless the couple with a child and it was only in "Lucifer" Season 2 that he realised Chloe's purpose. She was a gift from God to Chloe's parents.
This would then explain why the detective is immune to Lucifer's charms. Only Amenadiel, Lucifer's mom, and Maze knew about this part of Chloe's existence.
"But this has really bothered me, that Lucifer hasn't realized that if God put Chloe in Lucifer's path, and Chloe is what keeps Lucifer on Earth, that God has clearly planned for Lucifer to not return to hell. I mean, until now with the whole needing to keep the demons in hell," another Lucifan chimed in.
It would be interesting to find out what Lucifer's reaction would be when he finds out that God put Chloe in his path. Perhaps he hears it straight from his father when he comes to visit his sons on earth. After all, "Lucifer" Season 5 has already cast Dennis Haysbert to play God. Set photos also revealed that God and Lucifer share a scene together in the series.