All of which leads into another of my favourite subjects: well developed anti-heroes and villains with believable motivations and ambitions. Not that I don't love my heroic characters as well, but, good characters aren't the only interesting ones.
Real people generally aren't 100% good or evil. People do bad things with the best of intentions, or ignore widely held beliefs of what is right, because they genuinely believe that their way is better. Or people do something they know to be wrong, but its consequences have a positive effect on other people.
So what makes an enjoyable and engaging anti-hero? Someone who is working for the wrong side, but who believes they are in the right? Someone who knows their actions won't win them many friends, but whom the reader finds themself rooting for anyway? Someone who steadfastly refuses to acknowledge that they will be the one to save the day, but does so anyway?
Then there's the borderline case: the character who would be a villain, but for one redeeming feature. The gangster who loves his mother. The ex-gangster who comes back for one final job, because her family or friends need her help. The evil genius whose plans always backfire and benefit more people than they harm.
Which leads us back to the villain with believable motivations. Two characters were once friends, but fell out of favour with each other when a plan they were executing fell apart. One blamed herself and vowed to do whatever she could to make up for that mistake while preventing others from going down the same path that she had been following. The second blames someone else, or a flaw in the plan, or maybe just fate. She vows to improve on her failure and continues along the same path, perhaps resenting her former partner for walking away.
One of those two would be cast as the (anti-)hero, the other as the villain of the story, but which would be which? Is it all just a case of which one is the viewpoint character, or the more obvious protagonist?
In the two stories I mentioned at the beginning I have two potential anti-heroes: Edward, Duke of Derby and the Captain. Edward is leading a double-life, in order to protect his mother from finding out a whole bunch of family secrets and to keep her and various family retainers in the manner to which they're accustomed. The Captain works for a regime he knows to be corrupt, but is loyal to the oath he swore at the beginning of his service, and believes that one day someone else will come along with the reforms that are needed.
Are those sufficiently believable motives to raise the characters from villains to anti-heroes?
How about you? What makes a villain you can believe in? Is there a point at which a villain (or a hero) becomes an anti-hero, or does it vary from character to character? What authors write the best villains and why?