Hal Jordan is the experienced Green Lantern who trains John Stewart in Lanterns.
Jordan is described as a legendary member of the Green Lantern Corps and a former test pilot. At the beginning of the series, he is approaching retirement and is temporarily filling the role of mentor to Stewart, a newly recruited Lantern.
Their partnership is central to the show’s structure. The two characters investigate a murder in the American heartland, creating a buddy-cop relationship within the larger science-fiction world of the Green Lantern Corps. The writers have described them as opposing forces whose personal relationship carries much of the story’s emotional mystery.
Hal Jordan and John Stewart are two of the best-known Green Lantern characters from DC Comics. Lanterns uses both characters in the new DC Universe, while Nathan Fillion’s Guy Gardner appears in a supporting role. Sinestro is played by Ulrich Thomsen and is connected to Jordan’s past.