Morrel is devasted, "carried away by friendship." he knows his friend is incapable of what he's been accused of and attempts to seek Villefort's indulgence.
Mercedes quickly loses hope and marries another, but she cares for Dante's until his death.
Fernand is thrilled at his imprisonment; he got what he wanted.... Mercedes.
Danglars is another happy camper. He masterminded the letter that led to Dante's imprisonment and reaped the benefits. He becomes captain of the ship when Dante is jailed.
Caderousse is the neighbor; he's jealous of Dantes and happy to see him gone.
Dantes father never gets over the loss of his son.
Chapter 5 Quote; just after Dante's arrest;
"A despairing cry escaped the pale lips of Mercedes; the old man sank into a chair."