JD is a Jasper Doll, an artificially created biological weapon engineered as an obedient, emotionless combat artifact. Originally property of the Foundation, he escaped into a nearby forest after a laboratory accident. Discovered there, he was adopted by the Dragon Tribe, becoming the tribe leader's adoptive son. A persistent young boy named Kai befriended him despite his initial emotional void. JD's capacity for feeling first stirred through a deep fascination with a sunflower; this experience sparked his ability to smile and express emotion. Kai's subsequent death profoundly impacted JD, driving him on a journey dedicated to protecting people from Thanatos and bringing smiles to their faces. Fearful of recapture by the Foundation, he avoids them whenever possible.

He later joined the Aube Hunters, an organization dedicated to eliminating Thanatos, after encountering its members during missions. His mechanical nature as an artifact became a source of conflict when a system failure caused his collapse, revealing his true origins to the group. This prompted Angelique and Hyuuga to seek a cure, traveling to locations tied to his past like the town of Kozu. Though initially intending to leave the Aube Hunters afterward to avoid burdening them as a "defective" artifact, he chose to stay upon realizing his friends valued him for his identity and emotions, not his mechanical status.

JD exhibits consistent kindness, gentleness, and a nurturing disposition. He expresses care through actions like cooking, often baking cookies or scones for others, and maintains a focus on seeing others happy, particularly Angelique. In combat, he wields a pair of tonfas effectively against Thanatos, supported by proficient melee skills. His foundational relationships within the Aube Hunters—including Angelique, Rayne, Nyx, and Hyuuga—are built on mutual trust and camaraderie forged through living and fighting together. His background as an artifact and his journey toward emotional acceptance remain central to his role within the team.