Hatred and Discipline is a short story that was released in 2012. It was part of something Blizzard was doing in the days before Diablo III was released. You can read Hatred and Discipline online (or download it as a PDF).
Blizzard revealed each of the five classes of playable characters in Diablo III, one by one, before the release of the game. There was a “Gathering of the Heroes” page (which has since been taken down) where players could watch a class video, and learn more about a specific class.
There was a short story that accompanied the information about each of the classes. Hatred and Discipline focuses on a Demon Hunter named Valla.
The artwork you see in this post came from the Battle.net website. When Hatred and Discipline was posted, it used this artwork (but cropped it so that it focused on the Demon Hunter’s face.