The second Justice League Dark collection opens with Peter Milligan's last issues as writer, parts One and Three of the "Rise of the Vampires" story done as a crossover with I, Vampire. The TPB tries to minimize the crossover by leaving the part numbers off. But it's especially obvious that Part Three is setting up a conclusion that is not included. In isolation these two issues are unsatisfying at best, and skate close to incomprehensibility at worst. A good reminder of why I stopped reading DC comics (other than Vertigo) in the first place. They do feature Batgirl and Batman, and include the departure of Shade, The Changing Man from the team.
The collection gets back on track with "The Black Room" arc, which introduces new writer Jeff Lemire and signals the return of regular series artist Mikel Janin. Steve Trevor (who is now an agent of the secret U.S. military branch called A.R.G.U.S.) calls the team "Justice League Dark" for the first time. John Constantine's response: "That is the stupidest name I have ever heard." It adds Black Orchid to the team, finds vampire Andrew Bennett leaving, includes a visit to the House of Mystery, and--last but not least--features the apparent return of Tim Hunter. The last time Hunter was seen he had given up magic, and that still holds true when Madame Xanadu calls on him. She implores him to rejoin the magical community, and he informs her that he has given his magic away. Which leads directly into the "War for the Books of Magic" arc.
Despite my reservations about the series, I have to admit that I'm really enjoying the way it is weaving together all of the different aspects of the occult side of the DCU.
One thing I've noticed about these New 52 occult characters: they're generally quite close to the older appearances in the DCU. That makes them quite user-friendly for longtime readers like me (in fact some of these characters even predate the Mature Readers & Vertigo appearances that I'm most familiar with). Presumably they're reasonably approachable for new readers as well, because they get introduced and demonstrate their abilities in action pretty quickly.
The mysterious character behind the quest for the Books of Magic turns out to be the first big retcon so far. He's Nick Necro, a mage who was mentor to both Constantine and Zatanna. This introduces both a new character and a history that surely would have played a part in earlier stories, especially in the series Hellblazer and The Books of Magic. It's a very superhero story telling technique, introducing a human arch-enemy for Constantine, his Lex Luthor or Joker.
As the conflict ramps up, Lemire brings in more of DC's occult history, including the House of Secrets, Frankenstein, Agent of S.H.A.D.E. (in the form appearing in the New 52 series, based on Grant Morrison's Seven Soldiers series), and Amethyst (also previously brought back to the New 52 in the series Sword of Sorcery). After more big battle scenes--there's far more of these than in any of the previous appearances of these mystical characters--Timothy Hunter gets his magic back, grabs the Books of Magic, then disappears through a gateway, with Zatanna tagging along. That's quite a cliffhanger!
Another thing I meant to mention: Lemire really made a virtue of the 0 issue and Annual that were part of the DC publishing schedule November - December 2012. He used the 0 issue to introduce Nick Necro and his history with Constantine and Zatanna. We'd only seen him in shadows in the previous issue, which is a tease, since there's no way anyone could have identified him. He's a new character, as far as continuity is concerned. The Annual is essential to following the title, because it concludes the "War for the Books of Magic," and follows directly from the action in Issue #13.