A series of events, a number of heaven and hell personalities visits in Los Angeles, including Lucifer’s mother, his former flame Eve and Hell’s creatures determined to get Lucifer back as King or have someone else with royalty lineage to become their next king sped up the timing for what Lucifer must do.
Cain’s visit, the assassination of Lucifer’s mother, a psychiatrist doctor, Linda, carrying the baby of Amenadiel – eligible to become the next King of Hell – Chloe seeing the real scary monster look of Lucifer and secretly plotting to poison him, an army of Hell’s residents summoned by their leader to anoint the newborn baby as the new King of Hell put things in perspective for Lucifer.
As much as he enjoyed life on earth – dancing, sex, drinking and yes chasing criminals – deep down inside, Lucifer knew he did not belong here. He is after all the King of Hell. Anyone who would dare to challenge him – as those rogue Hell’s residents attempted to – would be damned! So Lucifer did what was expected of him all along, he returned to Hell.