William Fernie Buxton joined the Buxton family at age eleven after his mother Marguerite married Edward Buxton. He resented his stepfather Edward, stepbrother George, and stepsister Jane, clinging only to Marguerite for emotional support. Her death from illness plunged William into isolation until Jane offered kindness, recognizing Marguerite as her own mother. This act secured William's fierce devotion to Jane, though his bitterness toward the family endured.

As an adult, William worked at Buxton Bank and gained Edward's consideration as a successor. Secretly, he embezzled client funds and falsified records. When exposed, he vanished coinciding with George's expedition to Asia for cerulean sand. William stole George's watch and forged a report of George's execution for treason. Five years later, he orchestrated a masked airship robbery of Buxton Bank, deliberately planting George's watch to implicate Edward. The ensuing stress-induced illness incapacitated Edward.

William traveled to the Eastern desert's cerulean sand deposits, seizing control of a hidden technological city. He exploited the sand's properties to develop advanced aircraft like the Prominence, driven by scientific ambition and a vendetta against corrupt power structures—rooted in childhood marginalization. Masked, he manipulated events from shadows, pursuing more sand and targeting Barsac's expedition.

He surveilled Jane's quest to exonerate George and expose the sand's secrets. His tactics escalated to military aggression: deploying aircraft to raze settlements and crush resistance. Fixated on Jane as his sole source of past compassion, he confronted her unmasked during his empire's collapse. His final moments laid bare a psyche ravaged by isolation and resentment; he spurned redemption before his technology's destruction ended his reign.