Matt Ryan first played John Constantine in his own, short-lived NBC series. Unfortunately, the network failed to give the series a decent marketing push, so fans weren't really surprised when the show ended; however, a social media campaign to bring Constantine back soon followed.
Ultimately, The CW saved the character by giving him a cameo appearance in Arrow, and that led to the Hellblazer hero being added to the Legends of Tomorrow cast.
Due to plans for a Constantine reboot on HBO Max from J.J. Abrams and Bad Robot (it's set to feature a darker take on the character and will likely feature a person of color as the title character), Ryan's version is being phased out of the show. As a result, John's arc will wrap up in season six, but the actor looks set to remain part of Legends of Tomorrow...as a new character!
During a panel for the show during Comic-Con@Home, executive producer Phil Klemmer confirmed that Ryan will remain a series regular in season 7 as Dr. Gwyn Davies, an eccentric scientist from the early 20th century who might be the team’s only hope.
"As everyone who loves him knows, in the end, John Constantine will walk his path alone. The time has come for John to part ways with the Legends, and for me to part ways with John," Ryan says. "I’m really excited to be creating this new role on the show and having some fun with it — discovering how this new character fits in and causes some trouble for the Legends."
You can also check out a sneak peek at the rest of Legends of Tomorrow's sixth season below: