Prince Orm is the son of King Orvax and Queen Atlanna and half brother to Arthur Curry. Orm was coddled by his father and developed issues with his mother. Orm concluded the surface world would continue to kill Atlanteans and pollute the oceans, eventually destroying the planet and taking Atlantis with it.
After the invasion of Earth by Apokolips was stopped, Orm, in his Ocean Master guise, surfaced standing on the deck of a vessel with the dead King of Atlantis in his arms. Ocean Master blamed the surface dwellers and Justice League for his death and called it act of war. He vowed they would pay. Orm hatched a plan with his adviser Black Manta. A fake SOS beacon would be set up in the middle of the Atlantic Ocean. When a vessel from the surface world would investigate, Atlantean soldiers would be sent to attack to safeguard the location of Atlantis despite it being protected by magical safeguards. The S.S. California responded to the beacon and was sunk by four squadrons. The submarine's missiles were stolen and given to Black Manta. Manta disguised his vessel as the S.S. California and fired the missiles at Atlanteans harvesting kelp at the edge of the royal city. Orm used the incident to instill fear among his people and declared this was an act of war. Atlanna learned of Orm's plans through spies and instead decreed she would broker peace with the Justice League.
When Arthur Curry survived an assassination attempt, Orm relied on his pact with the Trenchers to make a second attempt which also failed. Irritated his plan was falling apart, Orm accused his mother of dishonoring the memory of his father because she had a bastard halfling son living in the surface world. Atlanna revealed she knew of Orm's agenda and declared his coup was over. While she was distracted with Black Manta, Orm stabbed Atlanna through the chest from behind. Orm took the throne and the Trident. He fabricated a story that Atlanna was murdered by a surfacer and mobilized an army. In his Ocean Master guise, Orm appeared to Curry, Mera, Cyborg, Green Lantern, Superman, and Wonder Woman as they mourned Atlanna. Orm boasted about killing her then neutralized them with the Trident's power. He encased them in pods and had them disposed of in the dark trench. Orm addressed the Atlantean army and generated a giant tidal wave. They marched to Metropolis on the eastern seaboard of the United States of America.
Orm and his army were met by General Sam Lane and the U.S. Army. Orm ordered all humans to be killed for Atlantis. Mera and the Justice League failed to stop Orm due to the power of the Trident. Arthur Curry held his own against Orm but likewise was no match for the Trident. Batman revived Cyborg and had him replay footage of Orm admitting to killing Atlanna. The Atlantean army realized they were betrayed. Orm attempted to cover it up as surface magic but Mera backed the video. Curry decked Orm and took the Trident. He managed to convince the army to stand down. Orm was arrested and taken to Belle Reve Prison. Orm was hysterical, repeatedly stating he was royalty and demanding to talk to his brother. He was soon approached by Lex Luthor, who had a proposition for him.