Moloch (MLK) is from Dexter in the Dark. He is the original Dark Passenger, a dark god, who rode pre-humans and forced them to kill each other for its amusement. When humans evolved, he got them to worship him, influenced their evolution to enable better worship, and started to reproduce, creating regular Dark Passengers. When he created too many, he started to kill off the offspring, which resulted in the creation of the multitude of gods, each with a cult to fight each other and Moloch. Most Dark Passengers who do not serve Moloch run away, to prevent from being killed. Cody Bennett's Dark Passenger is one of the few to stand up to Moloch, unlike Dexter Morgan's, which ran away.
Moloch makes people see things, hear things, see a bull-headed statue with a fire in its belly where sacrificial victims are burnt, and hear trumpets to compel worship.
Moloch was King Solomon's Dark Passenger, and had Solomon classify other Dark Passengers as demons that need to be killed.
With the presentation from the novel, it is apparent that Moloch is the One True God of the Israelites (King Solomon's people), and even more, the originator of all gods, and the literal creator of mankind.