Pepper, a student at Naranja Academy in Paldea, stands out with his purple hair and reserved nature. He often explores Glaseado Mountain alone, initially shunning interactions—even with fellow student Ohara—preferring solitude.

His past is marked by parental abandonment; his parent focused entirely on research within Area Zero, ultimately perishing in a lab incident involving Paradox Pokémon before the main events. This loss left Pepper emotionally isolated, relying solely on his Mabosstiff. When that companion suffered severe injuries from a Pokémon attack within Area Zero, Pepper dedicated himself to finding the rare Herba Mystica to heal Mabosstiff.

During the Path of Legends, Pepper teams up with the protagonist to battle Titan Pokémon guarding the Herba Mystica. This journey fosters his trust in others and successfully restores Mabosstiff, softening Pepper's once-abrasive demeanor. His newfound gratitude surfaces when he sincerely thanks Ohara after her aid during a Cetitan encounter on Glaseado Mountain.

Pepper later joins the protagonist, Nemona, and Penny on a critical mission into Area Zero to deactivate a time machine causing ecological chaos. There, he confronts an AI replica of his deceased parent, programmed to sustain the machine at any cost. This forces Pepper to face his unresolved grief and anger. The AI ultimately sacrifices itself to stop the machine, granting Pepper emotional closure.

His interpersonal growth shows in evolving dynamics: early friction with Nemona and Penny shifts to mutual respect forged through shared trials in Area Zero. Snarky exchanges with Penny fade into cooperative teamwork, reflecting his increasing social integration.

A post-mission incident involving mind-control via poisoned mochi briefly overpowers Pepper and his friends, but they overcome this external threat together, solidifying their bond.