The young Greek man who runs the coffee shop next door to George Wilson's garage, is the principal witness to the murder of Mrytle Wilson as well as a friend to Wilson. It is interesting that he is Greek, suggesting the myth-like characteristics of Jay Gatsby, who is larger-than-life in his magnanimity, splendid car, resplendent mansion, and lavish parties. In fact, Nick even compares Gatsby to the myth-like Roman, Trimalchio, in Chapter Seven of The Great Gatsby.
Michaelis humbly tries to console George and reason with him when Wilson avows that Myrtle was killed by Gatsby--"He murdered her." But, as he speaks, Wilson tells him, "God sees everything":
Standing behind him Michaelis saw with a shock that he was looking at the eyes of Doctor T.J. Eckleburg which had just emerged pale and enormous from the dissolving night.
Although he tells George, "That's an advertisement," Michaelis, for some reason, turns away from the window and looks back into the room. Like the archangel whose name he bears, the humble Michaelis becomes the messenger who tells the police that Wilson has been "acting sort of crazy" on the next morning when Wilson has disappeared.
Perhaps, in this chapter, Michaelis stands also as a messenger of the dominant theme stated by enotes of Fitzgerald's opus magnum: "Americans have wasted their potential, the original American Dream."