The Master of Synapse is the main antagonist of Heaven's Lost Property.
The sadistic and ruthless ruler of Synapse, Master enjoys torturing the Angeloids he owns (both physically and emotionally); he sees them as merely his playthings which he can do as he pleases, and discard as trash. He is condescending towards humans, and refers to them as "Downers", a trait that is also shared with his Angeloids. Because of his arrogance and belief that the Angeloids will always obey his orders, he is surprised when he witnesses one of them break their chain or go against his orders. He is usually seated at a throne with two Angeloids beside him. Like Daedalus, his face is mostly obscured in his appearances. He also creates an "Ultimate Air Defense System" called Zeus. His real name is later revealed to be Minos, named after the king of Crete in Greek mythology.