Jessica Claiborne emerges as a mysterious American figure whose childlike appearance starkly contrasts her true adult nature. She asserts prior service in the United States Army and functions as a highly skilled tactician, renowned for her unflappable composure during missions. Aligning with Tris, she joins the Knocker-Ups—a specialized unit combating dream-dimension entities known as Desaria or Weirds within the realm of Traumerei. Jessica operates alongside fellow members Ryuhei Oda, Aruto Fushibe, and Rena Mouri, leveraging her strategic acumen and steady demeanor against eldritch threats.