Justice League: Throne of Atlantis

Ocean Master attacks the surface in retaliation for Darkseid's invasion of Atlantis. He believes the surface world is responsible for bringing Darkseid to Atlantis and wants vengeance for the destruction and loss of Atlantean lives.

Early scenes show the devastation Darkseid caused in Atlantis, establishing Ocean Master's burning desire for revenge.

Queen Atlanna tracks down Arthur after the surface attack begins. She reveals that she is his mother and explains that his father, a human, was the reason she fled Atlantis. She tells Arthur about his true identity as the heir to the Atlantean throne.

Arthur's extraordinary aquatic abilities and his unexplained connection to water hint at his Atlantean lineage throughout the film.

Arthur initially refuses to get involved in the surface world's conflict, but he changes his mind when he realizes Ocean Master's plan threatens both Atlantis and the surface. He decides to fight alongside the Justice League to stop his half-brother's destructive path.

Arthur's natural protective instincts and his growing sense of responsibility foreshadow his eventual choice to stand with the heroes.

Ocean Master is motivated by revenge against the surface world for the death of his people during Darkseid's invasion. He sees the attack as justice for Atlantis and believes ruling the surface will prevent future threats.

The film establishes Ocean Master's grief and anger immediately following Darkseid's attack on Atlantis.

Black Manta works alongside Ocean Master as his ally in the assault. He leads attacks that create chaos on the surface and serves as a key commander in Ocean Master's plan to wage war against humanity.

Black Manta's alliance with Ocean Master is established early, showing their shared goal of destroying the surface world.

Arthur and Ocean Master are half-brothers, both sons of Atlanna. Their conflict stems from Ocean Master's belief that Arthur is a betrayal of Atlantis due to his human father. Arthur's existence represents everything Ocean Master resents about Atlantean royalty.

The revelation of their shared parentage adds personal stakes to their confrontation.

Arthur resents being abandoned by his mother and struggles with his dual heritage. He feels no connection to Atlantis and wants nothing to do with a world that rejected his father. His refusal stems from years of feeling like an outsider.

Arthur's isolation and his struggles with identity are established in his early scenes before Atlanna's arrival.

Atlanna searches for Arthur because she knows Ocean Master will stop at nothing to destroy the surface world. She believes Arthur is the only one who can stop his half-brother and prevent total war between Atlantis and the surface.

Atlanna's urgency to find Arthur highlights the severity of Ocean Master's vendetta.

Arthur defeats Ocean Master in their final confrontation, but chooses to spare his brother's life. This act of mercy, combined with Arthur's willingness to protect both worlds, establishes him as a true hero and the future king of Atlantis.

Arthur's earlier choice to protect rather than destroy foreshadows his merciful decision in the final battle.

Arthur's powers derive from his Atlantean heritage. As the son of Queen Atlanna and a human father, he possesses superhuman strength, durability, and the ability to communicate with sea life. These abilities remain dormant until he embraces his heritage.

Arthur's unexplained strength and water affinity hint at his supernatural origins.