Bill Weinberg, a mechanical engineer at Zack’s Gym, hones and enhances cybernetic prosthetics for combat athletes, serving as Levius Cromwell’s primary technician for maintaining and securing his metal boxing arms. His disheveled curls, glasses, and functional attire—shirts, pants, and suspenders—reflect his no-nonsense approach. A former frontline medical technician during the European war, his revoked license post-defeat redirected his efforts toward aiding war orphans while contributing to Mechanical Martial Arts as a military engineer, eventually forging his partnership with Levius.

Calm and methodical, he merges technical rigor with pragmatic ethics, exemplified by brokering Hugo Stratus’ medical funding to finance Levius’ upgrades. He navigates the political and military undercurrents of the sport, acutely aware of Amethyst’s exploitation of orphans and match-fixing for weapons testing. His interventions range from preempting prosthetic malfunctions to orchestrating emergency medical protocols mid-fight, while his technical acuity identifies vulnerabilities like Malcolm Eden’s flawed cooling systems. Unflinching in high-stakes innovation, he modifies Levius’ arm with compressed steam despite escalating risks.

After Levius and Zack Cromwell’s year-long coma, he oversees their rehabilitation and confronts post-recovery complexities, including managing A.J. Langdon’s amnesia. Balancing ethics with strategy, he collaborates with figures like Chamberlain to restore her combat-ready memories, favoring tactical utility over sentiment. A Grade II “Most Talented Engineer” awardee and Class-S license candidate, his reputation rests on innovating and sustaining mission-critical systems.

Though initially projecting financial detachment, his actions betray deepening stakes in Levius’ survival and countering Amethyst’s schemes. His clinical expertise intertwines with latent loyalty, navigating moral gray zones where technology and warfare collide.