Gilderoy Lockhart
Reasoning: The card of self-interest. This can be a good thing, as in making sure not to neglect yourself and your own well-being. However, it more likely means selfishness, dishonesty and immoral behavior. It can mean lies, tricks, "letting the ends justify the means", and is the card of bullies and braggarts. Gilderoy Lockhart is the most blindly self-centered character in the series. But beyond being an insufferable self-loving idiot, he is a criminal and a liar who has based his entire image on the stolen achievements of others.
In a traditional tarot deck, this is the Five (5) of Swords.
Notes
I had a hilariously good time with this one. I don't think I've ever done a more colorful picture, and I know I've never used so many pinks and purples in one piece. It was surprisingly tough to get his infamous smile. I didn't know if he should be more exuberant and hyper, or more smarmy and slick. In the end I decided to make his expression more smarmy and slick, but kept his clothing exuberant and hyper. ;)