"In 20XX, after the fall of the "Quarantine Zone" to the Xenian Infestation, the Universal Union saw fit to upgrade it's Metropolice Units, issuing them higher grade firearms and munitions.

To be issued a weapon, a Metropolice Unit must submit themselves to be refreshed and resolved, which strips them of their memories and cognitive dissonance towards the Union and uploads the latest training and tactics from Overwatch."