Leo Rugazzi
Leo Rugazzi was a scientist and CEO of Rugazzi Industries, who created the Defence Drones.
His company was bought by Jack Robertson in late 2017, meaning that his ideas could be "turbo–charged". Robertson also provided the casing of the Reconnaissance scout as parts.
Leo, whilst developing the drones, found organic traces inside the casing, and cloned them to create a Dalek mutant. He kept the creature in a plastic box as a pet, but when he showed it to Robertson, he deemed it disgusting and demanded that he incinerated it.
While attempting to incinerate the mutant, it broke free from its cage and wrapped itself around Leo, taking control of his body. It used Leo's body to acquire materials and workers available from Robertson's companies to create a clone farm in Osaka. After cloning many more of itself to take control of the Defence Drones, modified to possess Dalek weaponry, the mutant found Leo of no further use. The Thirteenth Doctor, who had arrived to stop the Daleks, ordered it not to kill him, but it did so anyway. In his final moments, Leo apologized for everything that had happened because of his actions. (TV: Revolution of the Daleks)