'Supergirl': "For Good" Reveals That the Legion of Super-Heroes Will Fight SPOILER

Tonight's episode of Supergirl saw the return of Morgan Edge, but that wasn't the only return the heroes were talking about over at the DEO.

Spoilers for tonight's episode of Supergirl, "For Good," below.

During the first few minutes of the episode, Kara/Supergirl (Melissa Benoist) recounts for Winn (Jeremy Jordan) and J'onn (David Harewood) a nightmare she has in which she sees Reign with two other Worldkillers. As they're talking, Mon-El (Chris Wood) walks in and reminds them that Worldkillers may have been created on Krypton, but have been genetically modified so that things like kryptonite doesn't impact them. During this conversation it's casually mentioned that, despite Zod being dead, he reappears in the future, and the Legion battles him.

For those who need a refresher, Zod (Dru-Zod) is Superman's ultimate nemesis. The megalomaniacal Kryptonian has, like all DC Comics characters, had a few origin changes over the years, but generally General Zod was in charge of military forces on Krypton who, after a failed attempt to take over Krypton, was sentenced to exile in the Phantom Zone. But as for the Legion battling him, that could be a nod to a story from the Legion of Superheroes animated series where the team does battle with Drax Zod, a Kryptonian criminal who grew up in the Phantom Zone greatly influenced by evil forces. It's possible that the Zod the Legion fights in the future on Supergirl is actually Drax Zod, if they're truly making a nod to the animated series.

Zod is also appearing in other areas of the DC Universe currently as well. Lor-Zod, the son of Dru-Zod and Ursula, is appearing as part of the time-travel arc in Action Comics while Dru-Zod's mother and grandmother, Lyta and Alura Zod respectively, have both been cast for Syfy's upcoming series Krypton.

Of course, this isn't the first time Zod has been mentioned on Supergirl either. Last season when Rhea poisoned Superman with Silver Kryptonite, Superman started to hallucinate Supergirl as Zod. Deaf and blind to Supergirl's attempts to reason with him, Superman only saw Zod, attacking her as when Superman faced off with Zod previously (a fight that the show references briefly) the Man of Steel was deeply affected.

It probably won't go over well if Superman finds out that Zod pops back up in the future, so this might be a glimpse into the future Team Supergirl and the Legion want to keep to themselves going forward.

Supergirl airs Mondays at 8/7c on The CW.