Brought into Paragon City by the PPD after the Rikti War, the Paragon City Police Drones are small hoodlight-looking robots that patrol Paragon City and keep citizens (and heroes in need) safe. They are typically stationed at zone entrances (including the Paragon City Monorail stations) as well as some areas of high importance to the city (such as Atlas Plaza).
The drones con as Sentry, are invincible, have absolute accuracy to all villains, and always defeat villains in one hit, no exceptions, even in PvP zones. However, they can only attack one enemy at a time and have a small delay between attacks, so a large group of enemies has a small window of time during which they can still attack.
Drones also provide a perception buff to nearby heroes.