This is what we have been told so far. She comes from a place called Xebel, an underwater world that started out as a penal colony centuries ago when a group of separatists was banished from Atlantis during one of their many civil wars. Thousands were sealed off in the Atlantic behind an impenetrable, invisible field.
For centuries, they fought to escape what most today call the Bermuda Triangle, but they failed. Her father was the king, and he trained her from birth to be his ultimate weapon; to be his instrument of hate against the atlanteans. She embraced that hate without question or hesitation and became the leader of Xebel's Death Squad.
When a fissure in the field was discovered, a fissure that would only allow one of them through before it was sealed off, her father chose her. He chose her to find the king of Atlantis and assassinate him.
But then she met him, and she learned that the King of Atlantis was not anything like what she had been told. She buried who she was and where she came from. She became Queen of Atlantis, and a wife, and a mother, and a heroine. At least that's what we have been told.
Mera's Secret Origin
By Geoff Johns
Art by Ivan Reis