Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
This build works pretty well. You get a lot of bonus damage on your hits thanks to your AP. In addition your abilities are pretty powerful as well. You're not very squishy and you can play support very nicely using your Righteous fury (ranged attacks) to deal the bonus magic and attack damage.