Most Helpful Guy
Grey is a combination of dark colors, and light. The villain had a choice in life, to go to one side, or the other. Perhaps there is always the possibility of redemption for him.
In one of the stories I wrote, there was an evil wolf who betrayed his kind. He was lawless, and a murderer. He caused untold death and destruction to his community, who lived peaceably with mankind.
In the end, I couldn't bring myself to kill him. I chose to humble him, and have him return to his people.
I think in many stories, the author can like, in a way, the villain. There should always be hope for the villain, even if they do not want it. Or take it.