WARNING: The following contains spoilers for the Season 3 finale of Supergirl.
The third season of Supergirl marked the end of actor Chris Wood's tenure on The CW series. In the closing moments of the Season 3 finale, Wood's character, Mon-El, returns to the 31st century with the Legion of Superheroes rather than remain in the 21st century with former love interest Kara Danvers, Supergirl.
"The plan for Chris was always to have him on the show for two years," Executive Producer Robert Rovner said in an interview with TV Line. "We’ve loved telling Mon-El’s story, as well as the story we’ve told for him and Kara. We hope the fans felt that it was a satisfying conclusion."
Mon-El was introduced in the Season 2 premiere of the popular DCTV series after his ship crash-landed on Earth in a cliffhanger closing out the first season. As an alien Daxamite, Mon-El possessed a similar power set as Kryptonians and helped Kara defend National City as its newest superhero, while eventually striking up a romance with her. In a desperate bid to stop his mother from eradicating humanity to conquer Earth for Daxam, Mon-El sacrificed himself only to be transported to the 31st century. There, he fell in love with Saturn Girl and married her while forming the superteam called the Legion of Superheroes.
Complications arose when Mon-El and the Legion arrived in the 21st century, reuniting Kara and Mon-El in a love triangle that occupied much of the third season.
"They both have destinies in different times as heroes," Executive Producer Jessica Queller said. "What they did was the sort-of Casablanca decision of putting what’s most important to them -- which is saving the world -- first. It’s a little bittersweet that one destiny is to be a hero in this time and one’s destiny is to run the Legion in another time, but I think they grew a lot from knowing one another. They have respect for one another, and they have a respect for the decisions they respectively made."
While Wood has left Supergirl as a regular cast member, the producers have left the door open for the character's return in the future.
"We love working with Chris, so we’d love to have Mon-El back someday if the story takes us there and if Chris is available," Rovner said.