Grecos is a member of the Cult of the Snake who hangs out in the Satyr’s Tail with his associate Niro and insulting the other patrons; though, as they are likely speaking theives' cant, it is difficult to know exactly what they are saying.
After the Oracle's Chosen made a bit of a bodge job of trying to find out who in the bar were agents of the Cult, Grecos tried to follow Calliope. But he was unsuccessful.