Subjected to experimental procedures as a child by a faction within Guardian, Lucia Konohana—originally named Haruka Asahi—was modified for survival in a future Earth rendered hostile by environmental collapse, with the intent of cryogenic stasis for successful subjects. Lucia became the sole survivor, undergoing significant physiological alterations. Her body produces a potent poison fatal to living tissue upon touch and generates controllable vibrations. These adaptations caused secondary effects including loss of taste and other sensory changes. The project was terminated upon discovery by other Guardian divisions, leading to her placement in the Santa Brosia orphanage under her birth name. Defective suppressants failed to contain her poison, causing plant and animal deaths around her. This prompted bullying from other orphans who believed her cursed. A traumatic incident occurred when a caretaker died after Lucia touched her during a fever-induced loss of control, resulting in the orphanage's evacuation and cementing Lucia's belief in her own cursed nature. This trauma led her to wear gloves constantly and avoid physical contact, even after receiving more effective suppressants. She later reclaimed the name Lucia Konohana, given by project lead Brenda McFarden.

As class representative, Lucia enforced rules strictly, often reacting to infractions with violence. Her gloves and avoidance of touch, stemming from fear of harming others, were misinterpreted as fastidiousness. She maintained cool composure but displayed volatility when provoked or embarrassed. Despite her bluntness, she harbored a softer side, particularly around Kotarou Tennouji and Shizuru Nakatsu. Her reluctance to touch living things created friction, notably with Chihaya Ohtori who perceived it as arrogance. This conflict was later resolved through cooperative efforts, revealing the trauma behind her behavior.

Her abilities include emitting toxins lethal to most living beings and inducing destructive vibrations in objects, which can malfunction machinery. Consequently, she wields a katana in combat to avoid jamming firearms. These traits originated from genetic engineering intended for survival in a miasma-filled future environment. Daily medication suppresses her poison, though its efficacy wanes over time.

During Kotarou Tennouji's investigation into the curse of "Haruka Asahi," Lucia actively misled him to conceal her past. She intimidated individuals connected to the orphanage rumor and staged a possession to deter him. Kotarou deduced her identity after noticing inconsistencies in her intimidation pattern. Confronted at Santa Brosia, Lucia reiterated her belief in her irrevocable curse. In response, Kotarou used his Rewrite ability to immunize himself against her poison and embraced her as proof she could be touched without harm. This moment marked a turning point, with Lucia accepting his vow of companionship. Guardian intervened, confirming Kotarou's immunity and placing Lucia under their supervision. Later, her suppressants began failing, endangering even Shizuru who had partial resistance. This forced Lucia into isolation while Guardian sought new treatments, exacerbating her restlessness and emotional turmoil.

Within the crossover setting, Lucia appears in a chibi-fied style. Her abilities are portrayed through comical effects, such as causing clothes to disintegrate during a soccer match through vibrational contact with a ball. She participates in group activities, like forming a kendo club and engaging in the school culture festival, indicating integration despite her isolationist tendencies. These depictions retain her core traits—her gloves, combat prowess, and occasional violence—within the shared universe's context.