The Justice League's presence is already palpable to those who followed the latest Batman V Superman: Dawn of Justice trailer. Parademons and the Omega symbol are enough to tell fans that Batman and Superman alone cannot defeat Darkseid, and so the Justice League must be assembled.
It is obvious the Batman v Superman: Dawn of Justice is slowing building up the foundation of many Justice League characters. DC Extended Universe's are teasing fans with symbols and snapshots regarding Justice League: Part One. According to Coming Soon, the latest trailer of Batman v. Superman showed a scene what looked like Darkseid's minion, a swarm of Parademons. Though DC and Warner Brothers still haven't officially confirmed that the ruler of Apokolips will be featured in the film, that brief scene provides fans a hint of Darkseid's involvement in DC Extended Universe.
Charlie Schneider, a.k.a. Emergency Awesome posted a video on Youtube about Batman having a 'knightmare'. The Youtube user said that the Omega symbol burned into the ground suggests that Darkseid is indeed coming. The Omega symbol is not only used by Darkseid to brand those vulnerable to his corruption, but he also harness the Omega Effect, which gives him dozens of alien abilities. Darkseid is also known to resurrect the dead if he chooses to do so, and this might be connected to one of the clips in Batman v. Superman trailer that shows Superman walking above a hill of skulls.
Den of Geek also reported that the Dark Knight's whole desert vision involving Parademons and Darkseid's Omega Effect symbol is part of a hallucination or a nightmare sequence in Bruce Wayne's part. One could then infer that if Bruce Wayne has this vision, then it's possible that the Green Lantern and Aquaman will also receive this kind of unusual vision since their senses are more sensitive than that of the human Batman. Such dystopian vision is clearly a prelude to the Justice League movies where Darkseid will be the main antagonist
Comic lovers know that both Batman and Superman cannot defeat Darkseid alone, they need to have few more superheroes fighting alongside with them. For Darkseid to be defeated, Justice League must be assembled, and so far, DC/Warner Bros. is teasing the fans consistently.
