Shortly after his return to life from the Chateau d'If, Edmund Dantes, disguised as an abbe, pays a visit to Caderousse at the Pont du Gard Inn where he presents the innkeeper with a huge diamond in exchange for information from his past. In the course of their conversations, the "abbe" tells Caderousse
I know what happiness means as I also know what despair means, and I should never play with either of these feelings...
Indeed, Edmund Dantes is a changed man after years in a prison.--he was 19 when he went in, now he is 33. In Chapter 22 he is described:
His oval face had lengthened; his smiling mouth had assumed the firm and determined lines indicative of resolution; his eyebrows had become arched beneath a single pensive wrinkle; his eyes had a look of deep sadness in them, and at time gloomy fires of misanthropy and hatred would sparkle in their depths; his skin, hidden from the light of day and the rays of the sun for so long, as assumed the pale and soft colour which, when the face is encircled with black hair, amkes the aristocratic beuty of the North. The deep learning he had acquired was reflected on his face in an expression of intelligent self-confidence; in addition, though naturally tall, he had acquired the healthy vigour of a body continuously concentrating all it force within itself. The elegance of his wiry, slender form had given way to the solidity of a round, muscular figure. His voice, too, had undergone a change...it at times was gruff and almost hoarse. Moreover, his eyes, having been accustomed to twilight and darkness, had acquired the peculiar faculty of disitinguishing objects in the dark, like those of the hyena and the wolf.
Indeed, Dantes is much altered from the naive, innocent young man who told his father that he had no enemies. He has learned much in the East, especially patience and deliberation, his personality now is not so generous and trusting. Instead, he is a harder man whose carefully wrought plans of revenge work out well.