Aquaman

Arthur ruled Atlantis for a while. He learned he had a younger half-brother, Orm, who was steeped in the old traditions and prejudices of Atlantis; Orm served as the acting king when Arthur was away. During his initial reign, Arthur began an initiative to recover the weapons of the Dead King of Atlantis, the undersea kingdom's first monarch. Of these weapons, Arthur kept the Trident of Neptune for himself. Around this time, Mera, a woman from an offshoot city of Atlantis who wielded great powers of aquakinesis, was sent by her people to kill Arthur. However, she fell in love with him instead, and he felt the same. The King of Atlantis had found a queen.

Arthur reestablished contact with the surface world, becoming known as the superhero Aquaman and helping found the Justice League. He clashed with Black Manta and other enemies, both above and below the sea, including the Dead King of Atlantis, who returned after millennia to retake his kingdom. At one point, Aquaman and Mera decided to leave Atlantis and live on the surface, ceding the throne to Orm, who had taken the title Ocean Master. However, Orm came into conflict with the surface world, and Aquaman and Mera fought and deposed him, reclaiming the throne of Atlantis in order to restore peace.

When Atlantis rose above the sea for unknown reasons, Aquaman and Mera not only had to keep their people alive, but they also had to convince the surface world that it was not an attack. While the Justice League was able to keep a tense peace, the Suicide Squad was secretly sent to sink Atlantis. Aquaman and Mera were able to fight them off and find a safe way to return Atlantis beneath the sea using an ancient mystic artifact. But this incident convinced them that better relations between Atlantis and the surface were needed. They established an Atlantean Embassy in Aquaman's surface hometown, Amnesty Bay, and Mera became the Atlantean Ambassador.

Atlantis was attacked by the Triumvirate of Sea Gods, who were imprisoned eons ago by the Atlantean demigod Arion. They had escaped their confinement and were aided by Lex Luthor's Legion of Doom. Among the Legion's members was Aquaman's old enemy, Black Manta. Mera made the decision to free Aquaman's half-brother, Ocean Master, from the royal dungeon where he'd been imprisoned for treason and asked for his help. Ocean Master's vast knowledge of Atlantean history proved useful. He helped Aquaman and Mera find Arion's hidden weapons, which Mera used to psychically reach the Triumvirate and negotiate peace. Black Manta, however, had already unleashed an alien creature called the Death Kraken. Aquaman was able to stop it but appeared to die in the battle, leaving Mera to rule alone.

Mera ruled with kindness despite her grief over Arthur, improving the lives of Atlantis' lowest citizens. More tradition-minded Atlanteans were offended by this, and Ocean Master led a rebellion against the throne. Aquaman, who had not died after all, returned, but not in time to prevent Ocean Master's overthrow. Aquaman and Mera retreated to Amnesty Bay, where they lived among surface people until the Frost King attacked Atlantis. Aquaman and Mera journeyed to the kingdom of the Fire Trolls, underwater beings who lived in tunnels below Atlantis, hoping to recruit them as allies. Initially, they refused, but after witnessing Mera's aquakinesis they were impressed and agreed to follow the royal couple. Together, they defeated the Frost King and reclaimed the throne.