Duke Frederick as a character is shown to be somewhat similar to Oliver. Both are in dysfunctional relationships with their brothers; just as Oliver has taken what was rightfully Orlando's and used it for his own benefit, so too, has Frederick taken the crown from Duke Senior and banished Senior from court. Duke Frederick is initially clearly a very evil character. After all, not only does he exile his brother, but also exiles his neice, Rosalind, because of his fear that she is more popular than his own daughter, Celia. However, just like Oliver, Duke Frederick is shown to experience a massive change of heart when he enters the Forest of Arden. Note how this is reported by Jaques in Act V scene 4, when he goes to the Forest of Arden with an armed force ready to kill his brother and end his alternative court:
Where meeting with an old religious man,
After some question with him, was converted
Both from his enterprise and from the world,
His crown bequeathing to his banish'd brother,
And all their lands restored to them again
That were with him exiled.
Duke Frederick therefore, after this conversation with an "old religious man," which is not directly reported in the play, relinquishes his power and also chooses a monastic life. I suppose Duke Frederick is inspiring through showing the audience that no matter how evil a character is, there is always hope of change for the better. Duke Frederick is clearly one of the last characters that the audience would identify as being able to change his ways, and yet by the end of the play this is precisely what has happened. He, like so many of the characters, has been altered by the magic of the Forest of Arden, or the pastoral influences that he clearly has so sorely needed. Duke Frederick therefore is proof of the fact that it is never impossible for a character to change his or her nature for the better, no matter how evil they have become.