Throughout Season 4, the characters undergo significant development, particularly Michael Scofield. As the protagonist, Michael's character is put to the test as he grapples with the consequences of his actions and the weight of his responsibilities. His relationships with his brother, Lincoln (Dominic Purcell), and his love interest, Sara (Sarah Wayne Callies), are central to the plot. The supporting characters also receive significant attention, with notable arcs for characters like Sucre (Amaury Nolasco) and T-Bag (Robert Knepper).