When she was a small girl, Maya Lopez's father, a Cheyenne gangster, was killed by his partner in crime, the Kingpin. The last wish of her father was that Fisk raise the child well, a wish the Kingpin honored, caring for her as if she was his own. Believed to be mentally handicapped, Maya was sent to an expensive school for people with learning disabilities. There, she managed to completely replicate a song on the piano. After that, she was sent to another expensive school for prodigies. She grew into a gifted and talented woman. Upon visiting her father's grave with Fisk, she asked how he died. Fisk told her that Daredevil had killed him.
Maya was sent by the Kingpin to Matt Murdock to prove Matt's weakness. He told her that Matt believed he was a bad person, and that she was the only way to prove him wrong. (As Maya believed him, it would not appear to be a lie when she told Matt.)
Matt Murdock and Maya soon fell in love. She later took on the guise of Echo, hunting Daredevil down. Having watched videos of Bullseye and Daredevil fighting, she proved more than a match for Daredevil. She took him down and nearly killed him, refusing only when she found out Matt and Daredevil were one and the same. Matt managed to correct the Kingpin's lies. In revenge, Echo confronted Fisk and shot him in the face, blinding him and starting the chain of events that would lead to his eventual downfall. (Kingpin would later partially recover his eyesight through reconstructive eye surgery).
After realizing the horror of her actions and the lies she has grown up with, Maya fled the United States to do some soul-searching. When she came back, she tried reuniting with Matt Murdock, only to find out he was now with a blind woman named Milla Donovan, and that the Kingpin was still alive (despite Maya's attempts to kill him). Leaving Matt, Maya visited the Kingpin in prison, who told her that he didn't blame her for what she did, and that despite all that had happened, he still loved her like a daughter.
Unsatisfied and needing peace, Maya turned to the Chief, her father's old friend, noted for his wisdom. The Chief sent Maya on a Vision Quest to calm her soul. On her quest, she met and befriended Wolverine who helped her recover and may be attributed to her picking up Japanese values and knowledge of the Japanese underworld. Soon enough, Echo made peace with her past and was back doing performance art.
Recently, after being unable to join the Avengers for personal reasons, Daredevil recommended Maya to Captain America to help the Avengers seize the Silver Samurai in Japan. She donned a suit that concealed her identity as well as her gender and rechristened herself as Ronin. Maya was instrumental in helping the Avengers defeat Hydra, the Hand, and Madame Hydra after a pitched battle.
Ronin then returned to Japan to keep an eye on Elektra Natchios and focus on resolving the conflict between the Hand and Clan Yashida.