Lucifer Morningstar/Relationships

Charlie Morningstar
Charlie is Lucifer's daughter. In the pilot, it is implied that Lucifer does not believe in his daughter's plan to rehabilitate sinners. When Charlie calls Lilith to talk about her failed interview, she says, "I think Dad was right about me". Nonetheless, Charlie did take his words of dealing with demons to heart, such as Alastor.

In "Dad Beat Dad", Charlie reveals her parents separated and she hardly sees her father anymore, only hearing from him when he needs something. It's evident that Lucifer loves his daughter greatly as he has multiple frame pictures with her and Lilith when the three lived together and gets nervous when Charlie calls him as he wants it to be perfect, however he doesn't even know where Charlie let alone what she is up to these days despite Charlie reminding him she told him months ago about her passion project. It's suggested that despite his deep love her he focuses more on his problems instead maintaining a relationship unintentionally neglecting her. Despite having trouble expressing his affection for her, Lucifer wishes to spend more time with Charlie and desires to feel close to her as evident when he sings with joy after Charlie invites him to the Hotel.

Upon seeing her, he hugs her tightly and even threatens Razzle and Dazzle by reminding them their job of protecting Charlie. He first meets Alastor and the two get off on the wrong foot as Lucifer feels threatened by Charlie relying on him. He then meets Vaggie, Charlie's girlfriend, for the first time and hugs her with excitement before meeting the rest of the members. He and Alastor soon get into a singing match over who Charlie can receive more help from and Alastor infuriates him by insinuating he views Charlie as his own child. After Mimzy's introduction, Charlie takes her father on a tour, but Lucifer then tells her his thoughts on Sinners and the Hotel. When their attacked and Alastor defends the Hotel, Charlie is upset that Lucifer has no faith in her or her dreams. Lucifer soon breaks down as he explains how Heaven let him down when he tried to help and despite their strain relationship, he will do anything to protect her from getting hurt and punished the way he was. In turn, Charlie tells him about her memories of the stories he told her that inspired her and her determination to save their people. The two reconciliate as they come to learn more about the other.

For all his failings there is no doubt that he deeply loves Charlie and is protective of her, he won't hesitate to unleash his fury on anyone who dares to seriously harm her. In season 1 finale he shows up to fight Adam himself after he attacks and threatens Charlie, despite wanting nothing to do with heaven or the exterminations & knowing this could cause serious repercussions from heaven, clearly showing that he has no tolerance for anyone who harms his daughter.

This is likely why despite the fact that the denizens of hell have no respect for Charlie and have no problem insulting or mocking her none dare to cause her any serious harm no matter how much she aggravates them as Charlie is one of, if not the only thing, that can move Lucifer to take action especially when it concerns her safety.

At the end of season 1 his and Charlie's relationship is shown to have improved immensely, with Lucifer not only helping Charlie rebuild the hotel but admitting that Charlie has changed his mind and he sincerely believes in her vision now.

Lilith
In "Overture", Charlie tells the story of how Lilith and Lucifer would meet and fall in love. Together, the two gave Adam's second wife, Eve, an apple that was said to grant knowledge and free will. For this act, Charlie explains evil was born and as punishment Lucifer and Lilith were sent to Hell. Lucifer could no longer see the good in humans while Lilith thrived as the Queen. The royal couple would later have a child, their daughter Charlie and for a time, the three seemingly had a happy life together despite the constant dangers that came with running Hell.

Though little is known about their actual relationship outside of being married, they are revealed in "Dad Beat Dad" to have separated and according to Charlie, Lucifer and her drifted apart as Lilith seemingly took Charlie with her. It is unknown what caused the separation, but it is evident Lucifer continues to love Lilith greatly as he continues to wear his wedding ring and has become depressed as he works on his rubber ducks to distract him. It is unknown if Lucifer is aware of her disappearance or knows of her location.

Razzle and Dazzle
Razzle and Dazzle were gifted to Charlie by Lucifer during her childhood to act as her personal bodyguards. Razzle and Dazzle are protective of Charlie and the rest of her family.

KeeKee
Indicated as a family pet of the Morningstars, KeeKee is adored by Lucifer as he affectionately greets her while visiting Charlie.

Alastor
Lucifer does not seem to know Alastor before meeting him in "Dad Beat Dad", as he asks who he is and states that he does not know him from his radio broadcast. However, the two immediately do not get along. Shortly after Charlie introduces them, Lucifer suggests that Alastor is a has-been and insults the hotel's name. In response, Alastor cusses him out.

Additionally, Lucifer shows jealousy towards Alastor when the latter began showing off his "deep" bond with Charlie. This caused Lucifer to become increasingly insecure about his relationship with his daughter, and he began to compete with Alastor for her attention.

Mammon
Mammon considers Lucifer his "friend". Whether Lucifer affirms this friendship with Mammon is unknown.