Shado's father, a man named Tomonaga, was Yakuza and knew where a Yakuza fortune was hidden. Former OSS agents attempted to discover that fortune after the war, and killed his wife to make him talk; Tomonaga executed seppuku thereafter. The Yakuza took his orphaned child to be raised as their instrument of vengeance, and gave her to a master kyudoka, Yoshitomo, so he would raise her. They had the child tattooed with a dragon to mark her allegiances and giri.
Yoshitomo himself owned obedience to the Yakuza due to ancestral giri, and taught her in the way of Bushido and kyudo, until she became a master of both, becoming shado. She then was ordered to kill all the men responsible for the death of her parents, and left Japan for several years. Her path crossed Green Arrow's twice, on two of her targets. Green Arrow first opposed her, but collaborated with her on killing one of her targets. Later, Dinah "Black Canary" Lance, then Green Arrow's woman, was captured and tortured by Shado's last target. Admitting his vengeance was more important than hers, she let him kill the man.
The oyabun commanded that she cut off her own bow finger to atone for not killing the man herself, but Yoshitomo stopped that foolishness by threatening to shoot the oyabun, allowing Shado to flee. The fool gunned Yoshitomo down in anger, and Shado took his life.
Thus, war has been declared between Shado and a large part of Japan's underworld. They will either kill her, or she will destroy them; there is no other way.
Later Oliver would once again meet Shado. CIA Agent Osborne blackmailed him into hunting her down to find a treasure map. Oliver finally caught up with her in but as soon as he found her, she shot him in the chest with her own arrow. Shado went on to nurse him back to health, but it's soon uncovered that while he was healing and drugged from the medication that she had given him, Shado raped him. She later conceived a son called Robert, which Oliver would not discover until years later. After she had healed him she said that she'd mistaken him for one of her attackers and so he left without the map. When they met years later, Shado showed Oliver his son Robert and went on to tell him how she had raped him. She then told him she wanted him to have nothing to do with his son. She still lives calmly under assumed identities, doing what has to be done and raising her son to become an archer.
In the series Green Arrow & Black Canary it was revealed that Shado was forced to kill Green Arrow by Dr. Sivana in order to save her son, Robert Tomonaga, from an unnamed sickness. Dr. Sivana promised to heal Shado's son if Shado assassinated Oliver Queen. The shot that was supposed to kill Oliver Queen missed and hit his son, Connor Hawke. Afterwards, Connor's injured body was taken to try and lure Oliver into a trap. Shado later teamed up with Green Arrow, Plastic Man, Black Canary, Batman, Speedy, and Dodger and attacked Dr. Sivana's lab.
Black Lantern Green Arrow reveals to Black Canary that when Shado raped him, he knew what he was doing and called her Nightingale, Black Canary's nickname.
The New 52
In the rebooted DC Universe, Shado originally worked as a hired assassin for the Yakuza. However, she longed for the day she could get revenge on Ito, the Yakuza boss who hired her. She would get the chance when she met the archers Robert Queen and Simon Lacroix, who ended up paying her to kill Ito. Although Queen, head of a major corporation, originally went to Japan solely for business, he found that Shado, the greatest archer in the world, could assist him in his search for the "Green Arrow," a mystical artifact said to grant its owner true enlightenment, and possibly immortality. Queen and Shado also fell in love, and even had a daughter, Emiko. However, the Outsiders - the union of the "weapon clans" - appealed to Simon Lacroix's greed, convincing him to kill Queen and eliminate all competition to him becoming the new head of the Arrow Clan. Lacroix, now the villainous masked archer Komodo, kidnapped Emiko and raised her as his own, and handed Shado over to Count Vertigo of Vlatava, who imprisoned her in a dungeon for several years.
Shado would be rescued by Robert Queen's son Oliver - now a superhero coincidentally using the name "Green Arrow." After her rescue, she revealed most of the details of her life to him, as well as the real reason for her imprisonment: she knew the location of the Green Arrow.
Oliver and Shado confront Count Vertigo. He managed to get a shot off but die to Vertigo's powers, he only grazes his ear and suffered backlash from Vertigo's attack hitting the side of his head. While writhing in pain, Shado retrieved a car for them to escape and also killed Vertigo's advisor. Shado spared Vertigo so that he could tell Komodo that she had Green Arrow.
Shado later knocked out Oliver so that she could confront Count Vertigo, who'd come to Seattle to look for Green Arrow. However, on her way to meet him, Richard Dragon attacked her from behind. He then went on to easily defeat her, while telling her that she should inform Green Arrow that nothing else would happen in Seattle unless he wants it to and gave an ultimatum: Oliver can either follow the new rules or there won't be room for him anymore.
Shado appears in the Arrow TV series, portrayed by Celina Jade. In the show, she is Yao Fei's daughter, captured by Ed Fyers and used to blackmail the ex Chinese officer.
In the show, she was captured as an incentive for Yao Fei to assist Fyers. She is later freed, and continues teaching Oliver to use a bow. She seems to have fallen for Oliver, and despite his having some feelings for her too, he states he has Laurel at home, who he still loves. She apologizes, saying, "It wasn't the right time."