Stevia Vartla, daughter of Vanilla and Coconna Vartla, operates within her family's Gurfey settlement. She engages in local activities, including the covert transport of military equipment. Stevia coordinates the movement of a Scopedog shipment, secretly arranged by her brother Saltio for smuggling. During this operation, she discovers Chirico Cuvie concealed within the cargo. Recognizing Chirico's significance through her father's connections, she facilitates his journey to Gurfey.

Stevia participates in Gurfey's defense against external threats, actively supporting resistance efforts during an attack by the Black Lightning Brigade. In a critical confrontation orchestrated by Beswood Gar Gastelman targeting her and Saltio for elimination, Chirico Cuvie intervenes using a smuggled Scopedog, securing their survival.

Later, she assists logistical efforts in the broader conflict against the Black Lightning forces, with limited direct combat involvement. Stevia is present following the battle between Chirico and Titania, locating Chirico near Titania's defeat site. Within the Phantom Arc narrative, Stevia joins her family in efforts to locate Chirico Cuvie, aligning with the story's focus on revisiting past connections.