The fourth beast is technological. He has unnatural teeth of iron. He is massive. He doesn’t simply consume to get his fill like the second beast, the bear, with three ribs sticking out of his teeth. The fourth beast consumes to destroy; a maniacal appetite without end.
The fourth beast is the last beast. Daniel learns it is the last kingdom; and his dream and what it means disturbs him greatly. The last kingdom is a creature reminiscent of many last kingdoms, maybe all of them when followed to their logical end (certainly this was the case even of the last kingdom within myself before I finally fell apart). It is the kingdom of reason and enlightenment; which sounds gentle as a lamb and wise as an owl. Yet as this kingdom ages, it grows horns , and its teeth turn to iron; and it is a beast so stuffed with reason it goes mad and the glow of its enlightenment becomes radioactive.