The Demons in the TV series Lucifer are minor antagonists in its fourth season. They are malevolent entities that reside in Hell under the rule of Lucifer Morningstar where they would torture any damned human soul who is sent there.
After Lucifer was bansihed to Hell by God, the demons were born to serve his every command. He had them torture every tainted soul who was sent there. The first soul they ever tortured was Abel, the brother whom Cain murdered, where they learned the arts of torture by torturing him.
One of the demons Lilith was sent to Hell after she was replaced by Eve as Adam's husband. She then became the mother of countless demons known as the Lilim, including Dromos, Squee and Lucifer's personal assistant and best friend Mazikeen. However, her forced separation from Adam drove her to become bitter with her children to the point that she presumably never loved them.
Eventually, in 2011, Lucifer grew bored of Hell and left Hell to Earth with Mazikeen, leaving all of the demons unoccupied.
In 2019, Eve intended on returning Lucifer to Hell so she can be his queen, and so after murdering the fanatical Father Kinley, she told him to tell the demons to arrive on Earth to bring him back. Led by Dromos and Squee, they started murdering people so more demons arrive. After Lucifer told them he was not returning, they rebelled and intended on replacing him with his Nephilim son, Charlie. They even betray Eve, saying she is not their queen.
After stealing Kinley's vial from Lucifer's penthouse, they were about to send him to Hell just as Lucifer arrived with Mazikeen, Eve and Amenadiel, Charlie's father. They fought them until Charlie was saved and Dromos was left alone. After Chloe arrived, more demons arrived and nearly killed Chloe, ultimately enraging Lucifer into unleashing his true devil form. As they kneel before him, he orders them to return, in which they do.
In the end, however, Lucifer was forced to return to Hell to keep the demons in check, knowing that they will rebel against him again.