The confirmation comes not from a direct appearance by the Caped Crusader, but through a pointed dialogue featuring Kyle Chandler's Hal Jordan. During a conversation with John Stewart (Aaron Pierre) in Lanterns episode 6, Hal recounts how Nathan Fillion's Guy Gardner, who took over as Green Lantern after Stewart declined the Guardians' offer, developed his own unique Green Lantern signal in Rushville. Jordan notes that Gardner openly emulated "that bat guy in Gotham," a clear reference to Batman and his iconic Bat-Signal.

This casual mention carries substantial weight for the DCU. It implies that Batman is not only an active and recognized hero but also a figure whose methods and presence are well-known to other seasoned crime-fighters like Hal Jordan. For Guy Gardner, the inspiration is even more direct, suggesting a familiarity with Batman's operations that led him to adopt a similar signaling tactic. This deepens the nascent DCU's world-building, establishing a history for its heroes that predates their current narrative arcs.

The Lanterns series itself is known for its multi-timeline approach, exploring the rich past of the DCU. While Hal Jordan's current status in the 2026 timeline (the present day of the DCU) is ambiguous, with hints pointing to his demise, the historical context he provides is invaluable. The show previously hinted at Gotham City connections through Sheriff Kerry, who hails from Gotham and bears the surname Kane, linking her to Bruce Wayne's maternal lineage and his cousin, Batwoman. These subtle nods underscore a universe where Gotham and its resident vigilante are already integral parts of the wider heroic landscape.

Looking ahead, while a direct encounter between the current DCU Batman and Hal Jordan seems unlikely given Jordan's potential fate, the groundwork is laid for interactions with other Green Lanterns. John Stewart and Guy Gardner are prime candidates to cross paths with the Dark Knight. Rumors suggest that both Guy Gardner and John Stewart will appear in the Superman movie sequel, Man of Tomorrow, which is also expected to feature Adria Arjona as Wonder Woman. While Batman's inclusion in Man of Tomorrow remains speculative, the references in Lanterns firmly plant him in the DCU's current timeline, serving as an active inspiration for new and veteran heroes alike. This early confirmation ensures that when Batman eventually takes center stage in The Brave and the Bold film, his place in this interconnected universe will already be well-defined.