Detective Comics is my favorite Batman book and that's almost entirely due to James Tynion IV. His grasp of these characters is phenomenal. While a flashback to a young Bruce Wayne and Zatanna Zatara discussing magic might seem indulgent under a lesser author, here it is a joy to read even if it ultimately has little to do with the main plot. Such is the magic of Tynion's pen and his gift for gripping dialogue.
The artwork is as excellent as the story. I'm hard pressed to think of any artistic team who has captured the savage beauty of Gotham City as well as Alvaro Martinez, Raul Fernandez and Brad Anderson have here. I regret that Martinez' gorgeous two-page layouts cannot be properly conveyed due to the size of my scanner but they are simply gorgeous and guide the reader's eye perfectly.
If this issue has a flaw it's that for all the focus on Azrael and revising his background for the reality of DC Rebirth there's surprisingly little of Jean Paul Valley in it outside of the fight scenes. It does make more sense for Batwing to be explaining the Azrael costume's AI given how taciturn Jean Paul is but it still seems a bit odd.
The Final Analysis: 8 Out of 10. A solid issue that suffers only in its inaccessibility to new readers.