Erika Campbell is a prominent character in Lemon Angel Project, serving as a member of the titular musical group and a close friend to the protagonist, Tomo Minaguchi. At the age of seventeen, she is identified by her distinctive appearance, which includes tall stature, dark skin, and long white hair reaching her chest, complemented by blue eyes. Her birthday is January 27th, making her an Aquarius, and her blood type is O. Erika came to live in Japan from Brazil, reflecting her mixed heritage as her father is half Brazilian and her mother is Japanese. She moved to the country alongside her adopted brother, Takumi, who later became a famous rock star as a member of the band Third Sence.

Personality wise, Erika is an exceptionally bright and cheerful individual, often acting as the mood-maker within the group. She is characterized by her strong desire for harmony and friendship, consistently urging others to stop fighting and become friends. This amiable nature is coupled with a protective instinct; she is quick to stand up for Tomo and their mutual friend Saya, sometimes offering forceful help even when it is repeatedly rejected. Her background as a foreigner is a significant part of her character. She was frequently picked on by peers for not understanding Japanese culture, a form of alienation that partly motivated her to answer the casting call for the Lemon Angels, seeking a sense of belonging. Despite the challenges she faces, she sometimes embraces a playful side of cultural differences, such as dressing up as a ninja.

In the story, Erika holds the role of a foundational member of the second-generation Lemon Angels. As one of Tomo's best friends, she was the first to befriend her and remains a loyal and supportive presence. She is also a skilled cook, a practical ability that contributes to her nurturing role within the group. Her personal history occasionally becomes a plot point, as seen in an incident where she was manipulated by another character, Haruka, into believing she could meet her brother Takumi. This event, which resulted in him being unavailable, highlighted her emotional vulnerabilities and her yearning for connection with her family. Throughout the series, Erika develops primarily by reinforcing her role as a unifying force, consistently demonstrating that her initial desire to be part of a group evolves into a genuine commitment to protecting the friendships she has formed. Her development is not about drastic change but about proving her steadfast loyalty and helping to heal the rifts among the members. Her notable abilities mainly lie in her interpersonal skills and domestic talents; she is an excellent cook and skilled at sewing, and she also has a knack for creating nicknames for others.