The Sentinels are robots designed to hunt mutants. Though a prototype emerged in San Francisco in 1906, the modern Sentinels were created by Dr. Bolivar Trask. His intention was to use them to save humanity from what he saw as an impending threat to the species' existence due to the increasing numbers of emerging mutants. They are cold and emotionless, with deep, resonant voices that speak in a deliberate, monotone cadence. Their synthetic, metallic vocal quality contrasts sharply with their clinical communication, highlighting their role as a relentless, impersonal threat.