Rachel Benning is one of the four main protagonists of the anime Red Garden. She is a student at a private academy located on Roosevelt Island in New York City. Rachel comes from a wealthy family: her father is a lawyer and her mother is a model, and outwardly the household appears comfortable and successful. Beneath the surface, however, the family is troubled. Her father is often absent and keeps a mistress, while her mother struggles with alcoholism. Rather than confronting these problems, Rachel turns away from home life and immerses herself in a glamorous world of partying and socializing.

At school, Rachel is part of the popular clique and is regarded as one of its most attractive and fashionable members. She enjoys being the center of attention at parties, is admired by her peers for her taste in clothes and boys, and tends to look down on those who do not belong to her circle. Fashion and popularity are the most important things in her life, and she is characterized as emotionally fragile and prone to instability beneath her confident exterior. At the start of the story she is dating a boy named Luke, whom she is openly fond of.

Rachel's life is upended when she and three other girls from her school, Kate, Rose, and Claire, are killed and then revived as Animus, supernatural fighters who are forced to battle monstrous enemies at midnight in exchange for the chance to reclaim their original bodies and lives. Rachel is the first of the four to awaken to her superhuman abilities, instinctively displaying an inhuman leap during an early fight, though she cannot fully control this power at first. The burden of fighting takes a severe toll on her ordinary life. She grows distant from Luke, argues frequently with her girlfriend, and watches her social standing collapse as her former clique turns against her.

Rachel's central motivation is the desire to recover the life she lost, and she struggles more openly than the others with the psychological weight of her situation. Her despair deepens when she sees her friend Marie among a group of Animus who have given up and crumbled to ash, a reminder of what awaits those who lose hope. At the same time, the possibility of recovering her original body gives her a reason to keep fighting. Her relationship with Luke deteriorates further when he misinterprets her bond with Nick, a married literature teacher who becomes a sympathetic listener during her troubled nights. Over the course of the series, Rachel's relationship with Kate, Rose, and Claire deepens as the four girls, who begin with very different backgrounds and temperaments, gradually learn to trust and support one another, and Rachel becomes more resilient and more willing to rely on her new friends.

As an Animus, Rachel possesses heightened physical capabilities, accelerated healing, and a lower-than-normal body temperature. She can recover quickly from serious wounds as long as she holds on to the will to live, but if she truly gives up on survival she will disintegrate into ash permanently. Like the other revived girls, she experiences an intense thirst that must be managed, and lemons are shown to soothe this condition. She also needs to release her power through combat on a regular basis. Rachel's arc is defined by the contrast between her initial vanity and insecurity and the growing strength, solidarity, and sense of purpose she finds through fighting alongside the other girls.