Surprisingly, the web series, now titled
Constantine: City of Demons, debuted its first 5 episodes today without prior announcement:
http://www.cwseed.com/shows/constantine-city-of-demons/
Even more surprisingly, it's
not in continuity with the NBC series. It's a complete reboot, with a contradictory version of Chas Chandler and his family (they're English now, and their daughter is named Trish instead of Geraldine) and of the formative incident at Newcastle -- basically the same backstory, but with different details; it was only John and Chas who were there, not the larger "Newcastle Crew" from the show, and Astra Logue was white in this version.
Unlike the previous CW Seed web series,
City of Demons has no Arrowverse guest stars or continuity references. The only other DC character to appear so far is
Nightmare Nurse, a co-creation of the web series's writer J.M. DeMatteis. So at this point, it's unclear which of the two contradictory
Constantine series is the one that takes place on Earth-One. We've all been assuming the NBC series did, but since this version is actually from Berlanti Productions, it seems likely that it would supplant the NBC series as the canonical Arrowverse version of Constantine. Even though Constantine's appearances in the Arrowverse have all made use of the Bear McCreary theme music from the NBC show, while the animated series has a new theme by
Justice League Action composer Kevin Reipl.
To be honest, since Arrowverse Constantine hasn't referred to any characters or storylines from the NBC show except the Newcastle/Astra backstory, I've sometimes wondered if it would turn out that it wasn't in continuity after all. But I'm still surprised at this.
Continuity aside, I can't say I enjoyed the 5 mini-episodes so far very much. They're rather slow-paced, and needlessly gory, and so far there hasn't really been much character development for Constantine; other characters are talking about his personality traits, but he hasn't really shown them much himself. Maybe it'll get more interesting in the second half, but so far, I'm kind of left wondering what the point was.