He warned the Avengers at Hydropolis to stay out of the oceans but Namor’s piranhas nearly attacked innocent bystanders, leaving Captain America to save them at the last second. Namor’s Defenders saw Cap’s interference as an assault and began to fight. Namor threatened Black Panther with death and suddenly Russia’s Winter Guard intervened, seeking justice for crimes Namor and his people committed against the Russians in the Black Sea. A brutal battle followed but Namor ended the battle when he killed his piranhas and ordered his people to leave.
Namor continued to gather additional allies to his cause and sought out the Vodani, a race of people from the Vodan. His entreaties with them led to the deaths of their king Okun and his daughter Princess Kataw, who sacrificed herself. Namor’s plan to force an alliance with them helped him realize that he didn’t understand the Vodani culture.
He then threatened the Sea Blades to join him in his war efforts, with their leader Karris succumbing to his deadly threats. He began experiencing what seemed like PTSD from his time battling the Axis Powers during WWII. He began dreaming of an old, deceased friend from the war, Tommy Machan, who then manifested in his mind. Driven by this psychic projection, Namor launched several offensives on the surface world. His former compatriots from the war, Captain America, Bucky Barnes, and Human Torch (Hammond), tried to convince him to relent, but the Sub-Mariner beheaded Hammond instead and launched missiles at a coastal town in Maine—missiles that transformed the civilians into sea-breathers and Namor moved the ocean to help them survive. Namor then obtained the Serpent Crown and rebuffed Bucky and the Invisible Woman, who attempted to thwart his efforts. Cap and Bucky used Namor’s chemical weapon on themselves to give them the power to become sea-breathers and stop Namor and his allies. They traveled to Atlantis to retrieve a potential cure, Namor’s Genus Compound, but Roxxon stole it first. When Cap got ahold of it, but his efforts were spoiled when Roxxon agents fired on him and Namor, exposing them both to the compound, which transformed them into powerless versions of themselves.
Stranded on an island for weeks together, Cap appealed to Namor’s guilty conscience, believing there was still good in him. The pair soon found a Roxxon lab nearby and reclaimed the compound, restoring their powers. Namor ultimately rejected Machan, who had escaped his mind using the Crown and possessed Navy Commander, and his new lieutenant, Roman Peterson instead. Upon battling his enemy, he defeated him but his plan to execute Roman Machan was met with dissent from Cap, who warned him if he didn’t hand him over, Namor would be blamed for Machan’s machinations. Namor put his bloodlust to bed, departing in silence. Namor later sent a message to Cap expressing how furious Atlantis was over Machan and insisted he had destroyed the Genus Compound to maintain peace.
When the Dark Elf Malekith brought his War of the Realms to Earth, Carol Danvers, AKA Captain Marvel, requested Namor’s help in defending the planet. Namor refused but protected the seas and sent the Muspelheim Firesharks that had invaded the oceans and sicced them upon the Avengers at Avengers Mountain, sending a clear message that he still harbored ill will towards them.
When an Atlantean Dragon was captured by Mike Nguyen, CEO of the Big Nguyen Company, and used to power the city of Pan, the Pan-Asian portal city, King Namor granted the Agents of Atlas one day to return the dragon, or Pan would suffer the consequences. Agents of Atlas returned the dragon but once it was in Atlantis, it went berserk, leaving Atlantis in ruins again. Nguyen sent his allies, the Sirenas, to attack Atlantis and take their own revenge against Namor for the dragon’s destruction over the generations.