Namora was born in the kingdom of Atlantis, deep below the ocean, Atlantis' first mutant. Years later, another mutant child of Atlantis stepped forward. Attuma used his mutant might to kill Queen Dorma and attempted to seize her throne. Namora attacked Attuma and saved the kingdom. The people of Atlantis chose Namora as their queen, and she rewarded their confidence in her with decades of peace.
The world above the ocean was far less stable. After watching the surface dwellers destroy each other over two world wars, Namora decided she could not allow humans to eventually encroach on her kingdom. She led a preemptive strike on the surface world but was halted by a mental summons from Charles Xavier. She was shocked at the man's compassion for all people. Namora put off her invasion and offered her part-time services to Xavier and his X-Men, feeling an immediate kinship with these fellow mutants. If not for Magneto, a peaceful world may have been possible. Magneto's attack on the human populace led to mutants being hunted. Namora was horrified and decided to attack the surface world once again, beginning with those who attacked her genetic brethren. Namora killed the officially sanctioned heroes of the surface world - the Avengers - and even hunted down the Fantastic Four, the one team to speak out against the treatment of mutants, for standing by while mutants were murdered. Namora became ruler of the planet and, remarkably, it became a better place.
Many years later, Namora was visited by the Timebroker and unhinged from time. It is unknown as to what the Timebroker informed her would happen if she did not complete the missions, but it was obvious she was not convinced he had told her the truth. She attempted to sabotage her first mission with the team in the Earth-616 Universe by contacting Reed Richards and telling him the Exiles meant to tamper with the timestream.