Lanterns will be an exciting new chapter in the DC Universe, but there is one character who is going to be especially important for the future of the cinematic universe. Lanterns is the latest television series within the newly formed DCU, focusing on Hal Jordan (Kyle Chandler) and John Stewart (Aaron Pierre), members of the intergalactic police force known as the Green Lantern Corps.
These are two very important and exciting characters to introduce into the DCU. However, it is a character that fans have already been introduced to, who will be a very important aspect of Lanterns. Indeed, how this character works on the show will give insight into whether or not the DCU can really work as James Gunn has planned it.

Guy Gardner's Lanterns appearance will be a big test for the DCU
While Lanterns will focus on Jordan and Stewart as the main characters, it has also been confirmed that Guy Gardner (Nathan Fillion) will be back, having been the first member of the Green Lantern Corps introduced in the DCU. Gardner debuted in Superman while also having a cameo in Peacemaker season 2.
Gardner has already cemented himself as a fan-favorite character, with Fillion delivering a hilarious performance as the somewhat dim and very arrogant superhero. He is very much a comedic relief character, and how that type of character will work in Lanterns will be a test for the DCU's tonal shifts.
Lanterns has been described as a darker and more grounded series, akin to a crime thriller with superheroes. That feels markedly different from what we've seen in the DCU so far. James Gunn has pointed to this show as a telling example of how the DCU will attempt to tell very different kinds of stories, all connected in the same universe.
Lanterns has the difficult task of telling a very different kind of story that still feels like it exists in the same world as Superman. What is even harder is incorporating a character like Guy Gardner, who is also established in this world as a silly and decidedly not grounded character. Pulling this off is essential for showing that the DCU can handle these conflicting tones.
There have been crossovers at this early stage of the DCU, with characters from Superman and Peacemaker appearing in both projects. However, despite one being PG-13 and the other being R-rated, they still share the same distinct James Gunn voice. If Guy Gardner feels out of place in Lanterns, the shared universe concept could shatter.

Guy Gardner needs to work for Batman to work
Guy Gardner is certainly not the most important DC character, but ensuring that he can exist in a darker story will make it easier for more iconic characters to come along. If a comic relief character works in a darker story, then a darker character can work in Gunn's brighter DC Universe projects.
Batman is obviously going to be a key character in the DCU, with The Brave and the Bold as one of the first movies announced for the new universe. However, he is also a character who is hard to see working in Gunn's style. That could all change if Lanterns pulls off Guy Gardner well.
If Gardner doesn't come off as a silly joke amid this brooding thriller series, then it makes it a lot easier to accept that the dark and tortured Batman can share the screen with David Corenswet's golden-hearted Superman. By the time these two titans share the screen, the audience needs to know that the brightness and the darkness of the DCU can coexist.
