Hazbin Hotel Staff
Vaggie
Vaggie and Charlie are a couple as well as best friends. Vaggie is supportive of Charlie as shown when she gives Charlie "the thumbs up" when Charlie starts her speech about the Happy Hotel. Vaggie is also very worried/concerned when talking to Charlie about trusting Alastor due to his reputation in the past. Vaggie is also extremely protective of Charlie, often threatening or harming people who threaten Charlie.
Alastor
Alastor assists Charlie with her endeavors. Even though she doesn't trust Alastor as an honest sponsor, Alastor's methods of reeling in more patrons to the hotel and his natural charisma have coerced Charlie to enlist Alastor's help. Despite this, she does keep a safe distance from striking a deal with the radio demon due to knowing his past and infamous quick rise to becoming an Overlord.
Husk
Husk and Charlie met when Alastor summoned Husk for a position as the hotel's bartender. While Charlie, at first, greeted Husk with open arms, Husk responded to the princess with surly indifference.
Niffty
Niffty and Charlie are friends and co-workers at the Happy Hotel.
Family
Lucifer Magne
Lucifer is Charlie's father. Charlie has mentioned that her father does not support her idea of the Happy Hotel, unlike her mother. Charlie's impressions of Lucifer are implied to be negative, due to an ominous silhouette of Lucifer appearing in "I'm Always Chasing Rainbows". But Lucifer is shown to care and Love his daughter greatly as he was the one to teach her how to "not take shit" from anyone and the one who granted her Razzle and Dazzle.
Lilith Magne
Lilith is Charlie's mother. She supports her daughter's wishes of opening the Happy Hotel. Although she loves her daughter dearly, it is shown that she is over-occupied with her duties as the queen of Hell to be able to even answer her calls. Charlie is shown to be comfortable confiding with Lilith over Lucifer, as Lilith is the first person Charlie turns to via call is her mother.
Razzle and Dazzle
Razzle and Dazzle were formerly Charlie's childhood dolls that were brought to life by her father and were made her bodyguards. They care about Charlie very much and are very loyal towards The Magne Family.
The von Elritch Family
Helsa von Eldritch
Helsa is Charlie's rival. The two butt heads with each other. Charlie is seen calling her a loser during her song in the show's pilot. Charlie seemed happy when Helsa was upset. It is also implied that their families have known each other for a long time, as in a portrait in the hotel, Lucifer, Lilith and Charlie are standing next to Helsa and her mother and father.
Seviathan von Eldritch
Seviathan is Helsa's brother and Charlie's ex-boyfriend. It is implied that their relationship grew toxic and that Seviathan became abusive towards Charlie, which led to their break up.
Others
Angel Dust
Angel Dust is Charlie's first patient at the Happy Hotel. They eventually became friends after the events of the pilot episode That's Entertainment. While making fun of the hotel's failure, Angel Dust notices how his taunting upsets Charlie. Feeling bad, he stops and attempts to comfort her, but, knowing he would only make it worse, instead walks away and leaves her alone.
When asked what his unfiltered thoughts of Charlie are, he says that her happy attitude sometimes makes him happy, however, it mostly annoys him because he thinks that Hell isn't a happy place to live in.
Katie Killjoy
Katie dislikes Charlie for more than just a handful of reasons. Despite being the princess of Hell, Katie herself has stated that she does not care about Charlie's status and frankly looks down on her and her dreams of rehabilitating sinners. Charlie did tried to be nice to Katie, but when Katie kept on ruthlessly making fun of her idea of the hotel, Charlie had enough and stole her pen while calling her a bitch. Even though it angered Katie enough for her to turn into her final demon form, Charlie didn’t hesitate to fight back.
Tom Trench
Though the two have not interacted directly, Tom laughs at her alongside Katie but didn't rag on her idea like Katie did. He is later seen to be set on fire by Charlie during the fist fight with Katie, which seems to be done by Charlie.