Pepper is a supporting character in Urusei Yatsura and one of the three members of the Three Girls Gang, a trio of junior students who aspire to become a legendary delinquent group. She appears alongside Sugar, who serves as the gang's leader, and the third member, Ginger. The three girls are underclassmen of Lum, Benten, and Oyuki, and they model themselves on the fearsome reputation those three supposedly earned during their school days, when they were regarded as the most formidable trio in the history of their school.

Visually, Pepper is a teenage girl with long black hair that reaches her waist and black eyes. Her usual outfit consists of a teal armored top and matching pants, white gloves, and a sky-blue accent, giving her a combat-ready appearance that suits her self-image as a delinquent. Like the other members of her gang, she is determined, persistent, and deeply competitive, and she will go to considerable lengths to prove that her group deserves to be considered the strongest.

The central motivation of Pepper and her companions is to surpass Lum, Benten, and Oyuki and take their place as the new legendary trio. They repeatedly challenge the older girls, mostly through simple pranks and behind-the-scenes schemes that consistently fail, although they never stop trying. In the trio's debut, they manage to steal Benten's iron chain by using a trick in which Ginger lies by the roadside pretending to be dead while nearby mushrooms release spores that put Benten to sleep. Their plans are elaborate in setup but rarely succeed in the long run.

In the story, Pepper functions as a recurring rival and comedic antagonist to Lum and her friends. Her most important relationships are with her fellow gang members, particularly the headstrong Sugar, and with the older girls she seeks to dethrone, especially Benten, whom the trio is most eager to defeat. She also has little interaction of consequence with the male lead of the series, Ataru, who dismisses the three girls and treats them as if they were still children.

Later in the series, it is revealed that the legendary reputation of Lum, Benten, and Oyuki was largely based on exaggerated rumors that spread after certain classmates of theirs transferred schools. Even when this truth comes to light, Pepper and her companions refuse to accept it, and they continue to compete over trivial matters in an effort to demonstrate their own superiority. In terms of abilities, Pepper has a distinctive special power that allows her to shed her skin in the manner of a snake, remaining fully clothed after doing so. This unusual skill is one of several special abilities possessed by individual members of the Three Girls Gang.