“Ordinary Man” is the sobriquet that Lestat gives to Memnoch the Devil when he first encounters him, not fully understanding that he is a supernatural being. When Memnoch reveals his true form with wings, talons, and hooves, Lestat no longer refers to him as ordinary.
The “Ordinary Man” sobriquet appears in Memnoch the Devil (1995). For more perspectives on this sobriquet, read the Alphabettery entries Dora, Memnoch, Lestat de Lioncourt, and Roger.