Shiron Byacornise existed over 300 years prior to the series' main events. Endowed with the supernatural power to perceive the future in her dreams—though blind to her own fate—this prophetic gift marked her as a target from childhood, resulting in relentless persecution and forced displacement. Wizahk, an early Shindeki Church leader, exploited her naive youth, fulfilling her deepest desires to manipulate her powers for his own ends.

Despite her kind and selfless nature, Shiron's actions under Wizahk's influence inadvertently triggered the resurgence of the devastating Dragon Pneumonia, which killed thousands. Horrified by this catastrophe, she journeyed across the land tending to the afflicted, seeking redemption. During this period, she became the bearer of the Ever-Laughing Blade Schlamuffen, one of the Eight Divine Weapons, gaining immense power and the moniker "Ever-Laughing Witch." To avoid recognition and prevent alarming others, she adopted the alias "Calico" among strangers.

Shiron's later life was defined by guilt and isolation. Her prophetic abilities persisted, allowing her to foresee that her "Book of the Dead"—a stone-like artifact holding her memories and experiences—would eventually be discovered by Colio Tonies, a Meat (brainwashed human bomb). She embedded a message within the book specifically for Colio, using her powers to communicate across centuries. After her death, the book entered the Bantorra Library's collection, ultimately reaching Colio as foreseen. This message became her enduring legacy, crucially guiding Colio's actions during the conflict between the Armed Librarians and the Shindeki Church.