In the original 1st edition Monster Manual, Demogorgon was easily the most powerful demon lord, while Asmodeus💴 was the most powerful arch devil. Between the two, Demogorgon was probably a hair more powerful than Asmodeus.

Asmodeus was technically a deity, but💴 was exempt from many of the rules regarding divine beings, his actual status a matter of debate that had changed💴 over time. At the very least the strongest archdevil, weaker interpretations cast him as not even a full-fledged god or💴 possessed only of the powers of a lesser god.