In a little over a month, Aquaman will open in theaters everywhere showing Jason Momoa's Arthur Curry reclaim his destiny as the King of Atlantis. However, the DC superhero won't find the road to the throne without any enemies.

A new promo from the upcoming DCEU film shows Mera warning Arthur Curry that his half-brother Orm, better known to comic book readers as Ocean Master, is leading an army to take over the surface world.

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Sporting a comic-accurate outfit, Patrick Wilson's Ocean Master is seen leading an Atlantean army riding sea creatures into a bioluminescent battle under the sea.

Also seen is more footage of Yahoo Abdul-Mateeen II's Black Manta fighting Aquaman in a small, coastal Italian village, tackling the hero through a building to the dismay of its elderly occupant.

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"Scusi," murmurs Aquaman sheepishly before leaping back into the fight.

Directed by James Wan, Aquaman stars Jason Momoa as Aquaman, Amber Heard as Mera, Patrick Wilson as Ocean Master, Willem Dafoe as Nuidis Vulko, Yahya Abdul-Mateen II as Black Manta, Temuera Morrison as Thomas Curry, and Dolph Lundgren as Nereus. The film opens on December 21.