Dai-Long Lang
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Dai-Long Lang was a well-known detective in Zheng Fa who was the father of Shi-Long Lang and the head of the House of Lang until his death. Dai-Long was the head investigator of the SS-5 Incident, but the case would ultimately cost him his career and tarnish his family's name.

Involvement in the SS-5 IncidentEdit

Main article: SS-5 Incident
Teikun n lang

Shaking hands with Teikun Ō.

The SS-5 Incident began when the president of Zheng Fa, Teikun Ō, was apparently kidnapped on February 9, 2007. Dai-Long Lang, as the top investigator in his country, was called upon to head the case. The kidnappers demanded a high ransom, which they received, and the president was released and returned unharmed. However, the police found the body of Ryūji Kamei, a photojournalist, near the Happy Family Home orphanage where the kidnapping has taken place.

The murder investigation started at around 10:00 on the following day. They arrested the only suspect they had, the head of the orphanage, Marī Miwa. While investigating Kamei's body, the investigators found many inconsistencies, including the victim's bloodstain on the snow being apparently cut off and the victim's shoes not matching his shoe size. They also found a single photo on Kamei's camera, which showed an individual aiming a pistol at the president just outside the gates to the orphanage.

The prosecutor in charge of the investigation was Bansai Ichiyanagi. Unbeknownst to Lang, he conspired with Miwa and one of Ō's body doubles to kill the real president and replace him with the double. Ichiyanagi manipulated the evidence, replacing the samples in the blood tests so that Ō's blood could not be recognized. The photo which the investigators found was prepared beforehand, staged with the fake president and Miwa in a trenchcoat. Ichiyanagi's manipulation of the evidence allowed Miwa to escape conviction and be declared innocent in court, and he then blamed the police for failing to collect decisive evidence, thus tarnishing Lang's reputation and that of his family.

Lang realized that the prosecutor was corrupt and that he must have tampered with the evidence, yet he couldn't do anything about it. However, he did find a drawing by one of the children at the orphanage which apparently depicted Ō with the assassin Ryōken Hōinbō. Lang recorded the boy's testimony, but agreed to keep his identity anonymous in order to protect him from Miwa. Lang finally realized that the real Teikun Ō had been assassinated and that the current president was an imposter, but he decided to keep the information from the other investigators, due to a lack of hard evidence. Dai-Long Lang took this information to the grave, and it would not be until 2019 that the truth behind the SS-5 Incident would be revealed.


  • His Japanese family name ("Rou") means "wolf".
  • Lang's Japanese given name "Dairyuu" roughly means "big dragon".
  • "Dai-Long" is derived from "Dà Lóng", the Chinese reading of his Japanese name, and he retains this name in the unofficial English fan translation patch for Gyakuten Kenji 2.