Regi Blattaria

Regi Blattaria is a hostile character living in the Commonwealth in Fallout 4.

Background
Regi spawns after a certain level is reached in a bombed out building East of the Corvega assembly plant with a small army of radroaches, potentially including a legendary radroach. He carries either a minigun or Gatling laser based on player level.

Appearances
Regi Blattaria appears only in Fallout 4.

Behind the scenes
His roach army, and the fact that his name roughly translates to King Roach (Regi from Regis, while Blattaria is the latin name for cockroach) and his carrying a minigun all imply he is a reference to The Roach King from Fallout 3. There is even a toy rocket reminicient of the Roach King's throne on a shelf near his spawn point.
 * To support this, within the game's code his Editor ID is "POIRoachKing"