Bill Sikes represents the ultimate outcome of a brutalizing existence. He has almost completely lost any sign of human sensitivity or tenderness. Totally lacking in any kind of humor, he is openly scornful of anything resembling ethical or moral principles. Except for his controlling relationship with Nancy, Sikes has little regard for any human life, including his own. Regardless of what he has done or is about to do, he shows no sign of conscience — until, after having beaten Nancy to death, he finally understands that he has gone too far and is to be haunted by visions of his victim.
Sikes's seeming fearlessness is more a result of stupidity than anything resembling genuine courage. His behavior is a mixture of low intelligence and brute strength. Sikes advertises his intellectual limitations on frequent occasions. He never examines the fine implications of life outside the law with the caution that Fagin often applies. Neither does Sikes cultivate a healthy regard for the threats that can arise within the ranks of "the trade." Fagin wisely hides his hatred for Sikes, who, true to his nature, fails to see the value of suppressing his contempt for the older criminal. So Sikes prepares his own doom by needlessly needling Fagin and stoking his resentment.
In spite of their closeness, Sikes is singularly uncommitted in his relations with Nancy. First of all, he has no care for the conventions of his own precarious world to realize that his vicious mistreatment of the girl could be a dangerous practice. Fagin, on the other hand, understands this. Then, Sikes never suspects that Nancy's sudden odd and erratic behavior could have some disturbing origin; instead, he seeks to explain it away as the symptom of a passing illness. Fagin, on the other hand, recognizes beyond doubt that something out of the ordinary is troubling the girl.
Shrewdly understanding with whom he is dealing, Fagin maliciously stirs Sikes up before unleashing the man's fury with the news of Nancy's betrayal. Nor does Sikes consider the possibility of a trick but, prompted by his deadly foe, resolutely marches home to murder his only friend. He is a type of irrational evil, very close to being the embodiment of evil and meanness for its own sake.