Perhaps the main trait that these two characters share in this way is their physical appearance. Both are ugly and repulsive. Their deformed appearance is readily explained by their unnatural origins. Caliban is said to be the son of a witch and devil; the monster is cobbled together from dead body parts. They are also alike in being loved and understood by no-one. Victor absolutely abhors his creation, Prospero keeps Caliban as his slave. Caliban and the monster are outcasts from normal society, viewed wholly as alien, as The Other. Despite appearances, though, both characters can also be eloquent - indeed Frankenstein's creature displays high levels of learning - and they express desires of their own. Both want to mate and reproduce, for instance. They are not so far from normal humanity as other characters believe them to be, but they are cut off from normal human interaction.