The official synopsis for the fifth episode of Arrow Season 4 has been revealed. The episode is titled 'Haunted' and it features the first appearance of Matt Ryan's Constantine on Arrow after his show on NBC was cancelled earlier this year. The synopsis states:
When things take a turn for the worse with Sara (guest star Caity Lotz), Oliver (Stephen Amell) calls in a favor from an old friend who deals in the mystical, John Constantine (guest star Matt Ryan).
So, we can assume by episode 5 that Laurel and Thea will have already attempted to resurrect Sara and something has gone wrong (probably due to how long Sara had been gone before being resurrected). Oliver finds out and gets Constantine to help. I'd assume Constantine could use his magic to somehow help Sara channel her anger or something and also make the Lazarus Pit null and void, thus making the inevitable death at the end of the season more impactful because the Lazarus Pit can't be used.
The big part of this synopsis announcement, though, is the words "old friend." This could very well be an amazing spoiler as to whether Constantine will be appearing throughout the season.
I believe Constantine will appear in flashbacks and act as Oliver's ally against Baron Reiter (who, as Marc Guggenheim has said, will not become his comic book counterpart, Baron Blitzkrieg). Whatever Reiter has planned, it's something big and this might draw the attention of someone like John Constantine. We know some mysticism will come into the flashbacks, given Oliver's allusion to it in episode 1. So, will Constantine appear throughout the season in flashbacks and possibly in more present day episodes? I truly believe so!
What do you guys think? Let's talk about it in the comments!