In Macbeth, which characters (besides Macbeth and Lady Macbeth) choose greed over loyalty, and what does this do to their perception of loyalty?...

This
is an interesting question. Obviously, as you've noted, the theme of greed and how this can lead
to the destruction of loyalty is primarily embodied byhimself.

Early in the
play,tellsthat the "loyalty [he] owe[s]" to the king is so valuable that it "pays
itself," stating that all he is devoted to serving Duncan and protecting his honor.
Obviously, however, Macbeth's greed for power soon overtakes these feelings. Although his wife
at first convinces him to kill Duncan, he becomes increasingly greedy and more disloyal, even to
the point that he orchestrates the murder of his best friend, , rather than allowing Banquo to
live to "produce kings" (rather than Macbeth's line taking on the throne).

Macbeth's argument for this...