Kelly Kline

Kelly Kline was the secret girlfriend of President Jefferson Rooney, before becoming the mother of Lucifer's child.

History
Kelly began working for the president at an unknown time. She was considered trustworthy. After Jefferson's wife died, he and Kelly began an intimate and sexual relationship.

Season 12
When Lucifer possesses the president, Kelly unknowingly takes the archangel to her bed thinking it's her lover. While lying in bed, she explains to "Jeff" that she finds the secret nature of their relationship exciting, but she wishes she could be open about their feelings for each other, but knowing the public would disapprove, they are forced to stay quiet.

Kelly believes Jeff is still lonely after the death of his wife and Kelly respects that, but she hopes that one day the two of them could get married and have a baby. She also believes that Jeff truly loves her.

When Kelly suggests Jeff would make a great father, Lucifer is inspired to have a child with her and they sleep together a second time. After Kelly becomes pregnant, Lucifer expresses his delight, happy to have created something. Kelly is noticeably disturbed by his behavior and she realizes the president is acting strange, but she brushes it off as a result from stress.

Sam, Dean, Castiel, Rowena and Crowley eventually arrive at her location to inform her of the truth, that her unborn child is the spawn of the Devil, not the president. They convince her to lure Lucifer to her location. Once the president has arrived and the guards confirm the room is secure, Kelly informs Lucifer that she can't have his child, prompting Lucifer to choke her and insist that she does. Just then, the gang ambushes Lucifer, having fooled the guards into thinking no one was there.

After they successfully banish Lucifer, the gang urge Kelly to leave. Castiel escorts Kelly to a diner, where she manages to trick him into letting her go to the restroom, from where she escapes and enters a cab. She calls Castiel to inform him that, as the child's mother, she can't bring herself to get rid of it. She hangs up, leaving Castiel in a panicked state.

Her disappearance sparks concern for the Secret Service, with Rick reporting that he isn't sure whether she is alive or not. Castiel begins tracking her down soon after.

Later, Kelly was seen at a diner, her pregnancy was shown, when she was approached by a waitress, unaware that she was one of the angels sent to kill her and her unborn child. Later, after she was attacked, she was rescued by Dagon from Angels trying to kill her and Dagon revealed to her that the baby was a boy. Kelly was last seen walking with Dagon, who Lucifer senses.

Appearances

 * Season 12
 * LOTUS
 * First Blood  (mentioned only)
 * Family Feud

Trivia

 * Kelly is the first and only known woman to become pregnant by an archangel.
 * She is also the first woman confirmed to be the parent of a Nephilim.
 * She is the second-known woman to be in a romantic relationship with an archangel, the first is Kali, who was Gabriel's lover.