First of all: if you don't know the background to this OVA, i.e. if you haven't watched the Devils Line series, it's utterly pointless to start with this one since you just won't understand it. This is nothing but an extra episode which barely develops the plot and adds almost nothing to the continuation of the story. It is not a stand-alone, but it's basically made of several flashbacks which are very useful to explain and elaborate Anzai's past, a topic which isn't well covered in the regular series. The general quality (animation, art, etc.) is the same as the previous episodes. It's a good,enjoyable OVA that develops the almost untold story of the main character and it's nice to have something more from a 12 episodes anime like this that helps you understand what happened before the events shown in the main series. Recommended if you liked Devils Line and you want a little bit more of it.