This series actually go in pair with each episodes of the main series. Which I find nice. Unlike what you could find with picture dramas from Code Geas for example that requires you to have seen the whole show for it not to spoil you. I enjoyed it because it is more than just putting characters out of the show in extras where they do stuff. This can actually be both considered canon and develops a bit more the characters on a lighter tone than the main series. So far I have not often seen such extras and I find it refreshing.