Suffering from amnesia, the Sub-Mariner meets the Human Torch who drops him into the ocean to restore his memory, reviving his grudge against the surface people. Confronted by the Fantastic Four, Namor uses the Horn of Proteus to summon a gigantic sea creature which the Thing destroys. Finding the Invisible Girl attractive, he offers to cease hostilities if she agrees to marry him. But he is blown away into the ocean by a vortex generated by the Human Torch.
The Sub-Mariner meets Doctor Doom who offers him to join forces against the Fantastic Four and all mankind. After Namor has installed his magnetic grabber inside Baxter Building, Doctor Doom pulls the whole building into space with him inside and the Atlantean realizes that his partner has double-crossed him. He has no choice but to cooperate with the Fantastic Four and together they defeat Doctor Doom.
Learning of the Fantastic Four going bankrupt, the Sub-Mariner offers them to star in their own movie. After sending Reed and Johnny in action scenes against real threats, he fights the Thing personally whom he defeats when a lightning bolt momentarily transforms him into his human form. Namor announces his victory to Sue and asks her again to be his bride. When the rest of the team show up, Sue convinces him to respect his deal and pay them for their participation in the film.
The Sub-Mariner finally discovers shelters proving the recent presence of his people. Submitted to the Puppet Master's mind control, he kidnaps Susan Storm and challenges the Fantastic Four who come to Atlantis to fight him. The conflict ends when an octopus attacks the Puppet Master's submarine, releasing his control over Namor. After Sue refuses to stay with him because of her loyalty to Reed, Namor decides to focus on his search for his people.
The Sub-Mariner has finally found his people and is acclaimed as their ruler. He also reunites with his beloved Lady Dorma. After the prince has stated that human ships or aircrafts will no longer be allowed to trespass his domain, Reed Richards encourages the United Nations to fight the Sub-Mariner who then declares war on the surface people and invades New York with his army. Suddenly, the water in his people's helmets starts to evaporate, forcing everyone to retreat. Namor takes the Invisible Girl to his imperial amphibious craft. The other Fantastic Four arrive and fight Namor in the ocean. Seeing that Sue is drowning, the Avenging Son orders Krang and Dorma out of his command craft to take her to a hospital. Back in Atlantis, he finds that all his people have deserted him because he betrayed his people to save an enemy.
The Sub-Mariner convinces the Hulk to team-up against humanity. They start by attacking the Avengers, but when the Hulk apparently deserts the battle, Namor escapes back to the sea. He ends up on an ice floe where he unknowingly hurls into the sea the legendary Captain America, frozen in a block of ice. Later, the Sea Prince stumbles upon a troop of Atlantean elite guards who are still loyal to him. Namor and his warriors attack the Avengers on a small island and retreat when they are convinced that the team will be destroyed by an earthquake.
Namor kidnaps Susan Storm to Atlantis to convince her to become his bride, but when her teammates come to her rescue, she tells her abductor once and for all that her heart belongs to Reed.
Given a chance to join the Brotherhood of Evil Mutants, Namor learns that he might be a mutant himself. But when he sees how Magneto treats the lovely Scarlet Witch, he chooses not to ally himself with him. He helps the girl recover her brother Quicksilver from the X-Men, repels Magneto's attack and goes back home to Atlantis.
Namor has to defend Atlantis from Attuma and his barbaric army. When they breach through the city's defenses, the odds seem to turn in their favor. Outnumbered, Namor takes the battle to Attuma and counter-attacks in a hand-to-hand combat. Victorious, he banishes Attuma and his men from the realm, unaware that he has been secretly assisted by the Fantastic Four.
Thinking they are robots, the Sub-Mariner inadvertently kills two divers and brings their corpse to the Atlantean leader, the Holy One, where they realize that they are surface people. Fen explains how she met his father. While spying on the surface people who were disturbing the peace of their city, she fell in love with Leonard McKenzie, captain of the Oracle. She married him and gave birth to Namor. Fen tried to warn her people not to attack humans who were much too strong, but the Atlantean army attacked anyway and the surface people nearly exterminated their race. Now that he proved his worth, Fen sends her son in a war against humans to get revenge. Namor goes to the surface world accompanied by his cousin Dorma who assists him in an attack on Cape Anna Lighthouse.
Arriving in New York Harbor, Namor jumps off the plane and is sucked into the giant water pipe of a power plant. When he exits, he trashes the plant and flees to Central Park where he steals the clothes from a hobo. Tracked down by the police, he arrives at the house of a rich woman and saves her when her clothes catch fire. He tries to take her to his home world, but he lets her go when he realizes that humans cannot breathe underwater.
In New York Harbor, the Sub-Mariner spots a woman who is apparently drowning. He swims to her rescue and he soon realizes that this was a trap to capture him, yet he is stricken by her beauty. Spotting a British commercial ship under attack, he leaves the woman on a buoy at sea and destroys the Nazi menace. The woman, who is named Betty Dean, sees the Sub-Mariner rescuing the ship and understands that he may not be that evil after all. She tries later to get him to help the Allies against the Nazis instead of attacking America. The Sub-Mariner chooses not to take sides. He reports back home and convinces the Holy One to grant him the use of Atlantean forces to stop the human war.
Despite his effort to redeem himself by destroying Nazi vessels, Namor is arrested by the police as soon as he steps foot on New York City's waterfront. Confident that his good deeds has earned him the trust of America's justice system, Namor accepts to be taken to court to answer for his murderous attack on New York City, but he is still sentenced to the electric chair. The execution unexpectedly fails and the Sub-Mariner runs away, convinced that Betty Dean drugged him to prevent his escape. Heading home, he vows to get revenge of the surface people.
Frustrated that Americans have tried to execute him, the Sub-Mariner is granted permission by the Holy One to conquer the continent. Namor establishes his base at the top of the Statue of Liberty and goes on a major rampage over New York City. Betty Dean tries to reason with him, but she fails to convince him to turn back. NYPD then sends the Human Torch to confront him and they clash for the first time. The battle comes to a standstill when the Sub-Mariner entraps the Human Torch under a translite tube to stifle his flame but is unable to finish him off. Betty Dean convinces Namor to release the Human Torch, promising that the police and the flaming hero will leave him alone.
The Human Torch flies to the Sub-Mariner's domain and challenges him into a fight. To avoid hurting Sue's feelings, Namor tries to send her brother off without harming him.
Namor is attacked by Luther Robinson who led an expedition to Antarctic to prevent future attacks. While the ship and crew are destroyed, Robinson, his girlfriend Lynne Harris and another surviving crew member are captured by the Atlanteans, but the Sub-Mariner somehow decides to facilitate their escape to avoid the Emperor torturing them. But when their plane is found empty in the ocean, Namor reluctantly follows his mother's advice to capture Lynne Harris to make her his bride. He rescues the girl from a Nazi U-Boat right before an Allied cruiser destroys it and captures its crew. Namor submits Lynne to an operation that allows her to sustain extreme cold and to breathe under water. Luther rescues her right after the operation.
Namor forces Lynne Harris and Luther Robinson to come to Atlantis with him so he can carry on his plan to take the girl as his bride. He submits Luther to the same surgical procedure as Lynne to make him amphibious. The couple try to escape but in the end, they admit their defeat and resign to follow him back to Atlantis.
The Sub-Mariner takes Luther and Lynne to France where they prevent the Nazis from completing an undersea tunnel to invade England. Learning that the Japanese intend to attempt the same feat across the Bering Straight, Namor leaves his new comrades to fly to New York and get some help from the Human Torch. When Namor explains his visit, the Human Torch agrees to team up with him and together, they abort the Japanese's plan to build a tunnel between Siberia and Alaska.
Namor travels to France to pick up Robinson and Harris to take them back home. After a while they petition for a two-month leave to go to the United States, but the Prince refuses. Betty Dean and her Legion of Loyalists arrive in Antarctica and free the prisoners by gassing the Sub-Mariner. Going after them, he spots their plane is attacked by a Nazi ground base. After blowing it up, he agrees with Betty's suggestion to refocus his aggression towards the Nazis and the group helps him rebuild his army.
Namor finds a message from the Human Torch asking for his help and meets his new sidekick Toro. The Atlantean once more sets aside his animosity against the flaming hero and together, they destroy Nazi battleships. Later, he agrees to help out US War Department against another massive armada attack, which earns Namor public acclaim throughout America.
He sets out to win Karthon and the Lemurians as allies but gets caught by Llyra instead.
The Thing and the Human Torch intercept the Sub-Mariner on his way to New York Harbor. Furious of being betrayed, Namor leaves, convinced that Reed's invitation to a negotiation meeting was just a trap.
During a Nazi attack against Atlanteans cautioned by Hitler, Namor sees the Holy One hit by a pillar that apparently kills him. The Prince retaliates by destroying their submarine fleet. Then he returns home to supervise the reconstruction of the cities that were razed during the blitz.
At his return, Namor finds Atlantis in turmoil. After defeating Krang, Namor is able to find proof that Byrrah was behind the troubles. After his victory Namor proposes to Dorma, who accepts.
For help on his quest, Namor successfully tries to recruit the Silver Surfer and the Hulk.
Namor and his allies prevent a catastrophe regarding an experimental weather control station. Three Avengers guard the station, of whom Namor has to deal with Goliath.
Iron Man offers the Sub-Mariner to become an Avenger, but the Prince of Atlantis politely declines.
The Sub-Mariner visits Nelson and Murdock's law practice because he intends to legally claim his right to rule the surface world but Murdock tells him he has no case. Namor then goes on a rampage so they will have to arrest him and take him to court. After a short battle with Daredevil, he surrenders and asks for Murdock to represent him. But when Dorma shows up in court and announces that Krang is seeking to usurp his throne. Impatient to solve the matter, the Sub-Mariner breaks out of his cell, outmaneuvers the army and defeats Daredevil, then peaceful swims to his people.
Getting back to Atlantis to discover that Warlord Krang has usurped his throne, the Sub-Mariner undertakes a quest to recover Neptune's Trident which proves he is the rightful heir to the throne of Atlantis. During his quest where he is guided by Neptune's spirit, Namor finds his first clue which he uses to defeat the giant squid that was protecting it. He then proceeds to his next clue in the Forbidden Deeps where he defeats the Seaweed Man and follows the clue to find the Diamond of Doom that saps his life force while the Demon of the Diamond attacks him. After vanquishing him, he learns that Dorma has been sent to the land of the Faceless Ones so he decides to place his quest on hold to go and rescue her. When the Sub-Mariner is about to be defeated by their number, Neptune's spirit appears and announces that, by his selfless act of rescuing his loved one, he has proven worthy to claim the Trident and take back the crown of Atlantis. After taking Dorma to his palace for a medical treatment, he defeats Krang and exiles him from Atlantis.
