The word General refers to Satan's control over his minions in hell and in heaven during the revolution they fought. The word choice refers to the war in heaven and the idea that the angels are an army that Satan gathered to try to defeat God. Milton describes a scene of innumerable evil angels that are swarming like a plague of insects, to gather before Satan. Satan is commanding them much like a general might, and as he did before when he was their general in battle. In most cases of battle the general was not the first in command, in most cases it was the king or ruler of the period that was first in command. This idea symbolizes God's superiority to Satan. God is commonly referred to as our King. the word choice exemplifies Satan's power over his troop of fallen angels but also describes Satan as still under God, despite his falling from heaven into his own realm.