the primary antagonist of Metal Slug 4. As the head of the Amadeus Syndicate, the Doctor helps Morden to obtain new weaponry and also creating his own army.Not having any children of his own, he created various AIs to mimic them, as shown with White Baby and Iron Fortress as both are AI appearing as children, and has grown attached to them as a father figure.

Prior to the creation of White Baby, he created First Baby, but locked her away after she became extremely unstable.