Who is Colonel Mebratu from Cutting for Stone and what is their importance?

Colonel Mebratu arrives at Missing when he is being hunted by the Emperor for attempting to arrange a coup. Ghosh saves Mebratu's life in surgery, something for which Mebratu is forever grateful. Later, Mebratu's initial plan to overthrow the Emperor comes to fruition, but fails. Mebratu is shot in the head by his own brother during Mebratu's subsequent attempt at escape, but he survives. Three weeks later, he is hanged in the town square for treason.