He's the brutish character who says, "This island's mine, by Sycorax my mother, which thou tak'st from me"
[DOC] [TLE] Full text of ""The Tempest": Parallelism in Characters and Situations" [PAR] Both the light spirit and the brutish monster are equally desirous of freedom: 
Caliban .... when he says to those very conspirators: And this demi-devil  For 
he's a ...