A character who, although acting for primarily "evil" or selfish goals, is either not in full control of their actions or emotions and the reader or viewer can sympathize for due to them not being evil by choice, but rather by them being a victim of circumstance.
These villains can face a crisis of conscience in which they submit to doing evil, as well as having tragic pasts, which sometimes cause them to do their evil deeds. These villains often have confused morals believing that they are doing moral when in fact they are doing evil.
Even the protagonists can feel sympathy for tragic villains Often the hero will try to reason with the villain and implore him/her to stop their acts of evil. If the villain does do, he/she is usually redeemed. If not and is arrested or killed, the hero sometimes mourns him/her.