Lily Charles, better known as Aunt Lily, was believed to be the aunt of Charlotte "Chuck" Charles, whom Lily raised with her sister, Vivian, after the death of Charles Charles. Lily and Vivian were the members of a synchronized swimming duo called the Darling Mermaid Darlings, who claim that the reason they quit was the loss of Lily's right eye while cleaning the cat's litter box. Later, she revealed to Olive Snook that she is actually the mother of Charlotte.
Like her sister, Lily suffers from crippling personality disorders and social phobias, which have left the sisters shut-ins at their Coeur d'Coeurs house.
The Darling Mermaid Darlings
During their teenage years, Lily and Vivian performed as underwater artists as a two-woman act called the Darling Mermaid Darlings. The sisters were a celebrated and renowned pair that drew large crowds, especially by synchronized swimming event standards. However, as they continued to perform well past their mid-life years, their crowds grew lower and lower. Nevertheless, they clung to their fading glory as long as possible. 
The Darling Mermaid Darlings came to an end when Lily accidentally got dust in her eyes while cleaning the cat's litter box. Although Lily responded calmly to the incident with a quiet "oh my," the damage was startlingly serious and resulted in the loss of her right eye. Lily was unable to continue her life as a synchronized swimmer, and thus the team was disbanded. 
Life with Chuck
Following the death of Chuck's father, the eight-year-old Chuck moved in with her Aunts Lily and Vivian. Before long, however, the personality disorders they long suffered had blossomed into incapacitating social phobia, especially following the disbandment of the Darling Mermaid Darlings. As a result, the two practically never left the safety of their home and Chuck, who they gradually came to depend upon as a caretaker. 
Chuck and the aunts formed a strong connection, although Chuck's restlessness and the social anxieties of the aunts did create rough patches. Lily and Chuck, in particular, had difficulty getting along during the years when Chuck was going through puberty and Lily was experiencing menopause. Vivian also grew nervous eating her food because Chuck threatened to bake antidepressants into the meals she prepared for them,  which, unbeknownst to them, she did after she died and was brought back to life by Ned. 
Life after Chuck's death
During the immediate days following Chuck's death, Lily and Vivian felt their fears of the outside world were justified and they were even less anxious to leave their house, although they did welcome Ned and Emerson Cod into their house. In the course of that visit, Lily went upstairs to retrieve a suitcase full of two plaster monkeys that had belonged to Chuck. It was then that she was attacked from behind by the Shiny Shoes Killer, who put a plastic bag over her face and tried to suffocate her like he did Chuck. Lily, however, held her breath and pretended to be dead, which allowed her to find her shotgun and shoot the killer while he struggled with Ned. 
Although the newly resurrected Chuck was standing next to Ned at the time, Lily failed to see her because she was outside of the one-eyed woman's peripheral vision, and thus Lily and Vivian had no idea she was back from the dead. As a result of Lily's actions, she and Vivian collected the $50,000 reward that was offered for the capture of Chuck's killer. With the new finances and a newly found confidence, the sisters, arm in arm, left the sanctuary of their home and went traveling. 
Their newfound optimism quickly disappeared before their comeback tour as the Darling Mermaid Darlings when they got a late postcard from Charlotte in the mail from her Tahitian cruise saying "Wish you were here."
As of the fourth episode, Lily still thinks that Charlotte is dead. Although she almost saw her alive in the rear-view mirror of her car before disappearing behind a blade of the windmill. So she isn't sure if her one eye is playing a trick on her or not.
|This place knows things about me nobody knows.||: Lily|
|Like that you holidayed here thirty years ago and found a baby in a cabbage patch.
And by “cabbage patch,” I mean your lady parts.
In the season two premiere Bzzzzzzzz!, Olive is sent to a nunnery after having a manic episode at the Pie Hole. While visiting, Lilly explains to her that it was the same place she stayed when she had Chuck almost thirty years ago. Which makes sense since the Mother Superior assumed Olive was pregnant when she first arrived. When Olive asks why she never told Chuck, she explains that Vivian was actually Charles' fiancé at the time of Chuck's conception, and that they fabricated a story that her mother died in childbirth in order to hide the truth from her sister. Lily follows Olive to the Nunnery to make sure Olive does not bail. But Olive convinces her to return home, stating to not let go of Chuck and to take care of Vivian. In the episode Bad Habits, Chuck finally learns that Lilly is her mother after Olive tells Ned.
Chuck's plan of sunshine
Since Ned brought her back to life, Chuck has been finding ways to spread a little sunshine into her aunts' life.
The first phase was keeping true to her threat of baking antidepressants into her aunts' food, in the form of Ned's pies. She was given a sample pack from Alfredo Aldarisio. She often bakes cheese onto the crust of the pies. Darling Mermaid Darlings fan and Pie Hole waitress Olive Snook has been the deliverer of those pies. Because of those pies, moods of both aunts have been random. For example, Vivian would often giggle for no reason. Both Olive and Ned know of the pies but don't know about the antidepressants.
The second phase involved persuading Vivian and Lily to get back into the water. Once again, Olive was the messenger, but this time, she was more involved with Chuck. Methods include taking out Darling memorabilia and sparking the aunt's memories of swimming through the smell of chlorine (Both of which failed due to Lily's refusal to have anything to do with water). However, one rainy day, Vivian decided now was the time to leave their house and get back into the swim of things. She and Lily returned to do a swimming routine at the stadium that used to be the home of the Darling Mermaid Darlings'.
Personality and traits
Lily Charles, like her sister, has had a debilitating personality disorder since early life, which only became worse over time. Although both developed social disorders, Lily expressed even less social interest than her sister often presented through her less inviting demeanor and sardonic wit. Prior to a newly found interest in travel following Chuck's death, Lily was dismissive of the outside world. And though Chuck's death rekindled an interest in the outside world, that new interest quickly disappeared the moment Lily was reminded of Chuck's death, in the form of a postmortem postcard from Chuck that arrived just as the sisters were about to start traveling.
Lily shares with Vivian a love of fine cheese so strong that Chuck comes to refer to the refrigerator as the "Cheese Box" and the basement as the "Cheese Floor." Lily and Vivian also love birds, dozens of which are kept in cages within their homes. From her days as a synchronized swimmer, Lily also has the ability to hold her breath for a long time, a skill that particularly came in handy when the Shiny Shoes Killer tried to smother her to death.
Lily is highly protective of her sister given Vivian's overly trusting personality and health condition early in life. Kerplunk