Why is Richard III so profoundly evil?

Richard III: Why is Richard III so profoundly evil?
In the speech that begins Richard III, the title character gives us an explicit answer to this question: he is evil by his very nature. A misshapen hunchback whose image is unpleasing to the eye, Richard recognizes that he cannot be a lover and so he is "determined to prove a villain" (I, i., l.30).
Macbeth is ambitious, and like the protagonist of the Scottish tragedy, Richard seeks (and gains) the throne. But unlike Macbeth, there is no redeeming quality in Richard III, no "lady" with whom he shares a tender moment or even a Banquo to…