This article or section contains untagged major spoilers for the entire story, possibly including the manga. Readers who have not completed the story are advised not to proceed further.
The Official StoryEdit
During the Ushiromiya family conference, it is believed that a massacre took place. This was supported by the fact that everyone did not return and there is evidence that there was a huge explosion that took place. It is believed that the motive behind the murders was the fight over the gold that Kinzo Ushiromiya possessed. The case was not solved and several years later two message bottles were found that details the events that transpired. However, the problem was that the order of murders that took place were different, adding more to the mystery of the incident as well as adding interest to the public. The only thing that was certain was that both messages were signed with Maria Ushiromiya's name and both had the same handwriting, meaning that both were written by the same person. Later on a piece of Maria Ushiromiya's jaw was found as a result of the police investigation. Other parts of her body weren't found and neither of the relatives as well and it was hopeless to think that anybody that attended the family conference was still alive. Despite the contradictions, interviews with servants from Rokkenjima confirm that the author knew the mansion and its inhabitants in considerable detail. The only known survivor was Eva Ushiromiya believed to have been the culprit.
Forgeries and Popular TheoriesEdit
The discovery of the message bottle forgeries written by Sayo, sparked public interest. Some believed that it was a mystery, while some believed it was caused by magic. Others simply believed that they were only massacred. Due to its popularity, people began to make their own theories in the form of forgeries.
A loose-knit group, known as the Witch Hunt, attempts to put together the bits and pieces of information in order to determine the truth about Rokkenjima. A number of them write their own forgeries, with varying quality. A series of forgeries are released on the internet by a person calling themself "Itouikukuro Reigonamu". These contain details not released by the police or the Ushiromiya family. In addition, there have also been forgeries about Erika Furudo as having been involved in the incident, having fallen from a cruise boat in the waters near Rokkenjima.
As Eva was the only known survivor, the Eva Culprit Theory became the most popular. It was due to the fact that at the time it was the explanation that made most sense. However, after her death, Ange ended up inheriting all of the Ushiromiya family's assets that Eva inherited and the wealth she has built with it with the gold that she got with her. This made other people start the Rudolf's Family Culprit theory, as well as Battler Culprit theory. This was also found reasonable, because on the day of the family conference, they only brought Battler with them not Ange, giving the idea that Battler was brought to assist in the murders. Aside from the aforementioned theories, there also existed the George's Family culprit, which had George as one of the culprits.
Kyrie and Rudolf were indeed the culprits, as revealed later in The Book of Single Truth. It is because of this that Eva refused to tell Ange the truth of her parents being murderers, even on her deathbed.
The Book of Single TruthEdit
The Book of Single Truth, otherwise known as Eva's Diary, was a diary written by Eva that supposedly contains the truth of what happened on Rokkenjima on 4th and 5th of October. The exact contents were unknown and were even censored when one of the goats said what was in it. Whatever was in it contained a truth that Ange was not able to accept. The only clues available to its contents in the sound novels are scenes depicting the arrival of Rokkenjima via boat; Beatrice's portrait; Eva, Rudolf, and Hideyoshi; master keys; the epitaph being solved and the discovery of the gold; Shannon in her room; and blood, indicating murder.
However, the contents of the diary were officially revealed in the manga adaption of Twilight of the Golden Witch. It reveals that the truth presented by Bernkastel to Ange in Requiem of the Golden Witch was the truth.
The family conference had begun on Rokkenjima on October 4th. During dinner the family was presented with Beatrice's challenge of solving the epitaph. The adults were successful in solving it and discovered the gold room where Sayo Yasuda was waiting for them with four rifles that she admits she was going to use to murder them. She gives them the card with some of the gold already converted to useable money and reveals to them the bomb: 900 Tons of unexploded World War II ordanance and fuel underneath Rokkenjima wired to an antique clock that would destroy Rokkenjima at 12:00 AM if the switch was turned on. The meeting in the gold room quickly turned into a scuffle between the adults with them taking up rifles against each other. The first causality was an accidental discharge from Eva's gun into Natsuhi's eye. The fighting continues and Krauss is murdered as well. The remaining attempt to come up with a plan to hide the bodies. Rosa comes up with a plan which states that Eva and Hideyoshi confess to the police their guilt for the deaths of Krauss and Natsuhi, but she is shot by Kyrie. Kyrie and Rudolf decide to put a plan in motion so that they can hide all the bodies by blowing up the island and escaping to Kuwadorian with Battler if they can rope him into their plan. They begin by murdering the remaining adults and shooting Sayo as well. Kyrie and Rudolf then begin the mass murders. Rudolf is shown murdering George and Kyrie is shown murdering Jessica. Besides this no other murders committed by Kyrie and Rudolf are shown and are only talked about by Kyrie saying she used a knife to murder everyone in the Guest House which included Maria and the servants. Eva survived Kyrie's attempted murder as the bullet only scathed the side of her head. She then leaves the room to stop them. She meets Rudolf in front of the Chapel and kills him after knowing he murdered George. She then has a final meeting with Kyrie in the Rose Garden and the two have a final stand-off against each other. Kyrie's bullet once again barely misses Eva and Eva finally ends Kyrie's life.
Eva then escapes to Kuwadorian, the only place safe from the bomb's blast radius. It is shown in the manga that Battler finds Rudolf's body at the Chapel, and discovers the lion statue pointing towards the direction of the hidden gold. He enters the secret gold room and finds all the adults dead; where he saw Sayo (dressed as Beatrice). She brings Battler to the underground submarine area to shelter from the typhoon and was asked by Battler if Sayo was the "Beatrice" on the portrait. When she spoke, Battler recognized her voice, (who was Shannon), and confessed that she was Sayo Yasuda, who was Shannon, Kanon, and at the same time, Beatrice. She told Battler that she waited for him for the whole time and her plans about killing everyone including him and Sayo herself, but forgave her anyway since it was only an attempt and the ones who really did the massacre were Rudolf and Kyrie. He understands that Sayo was also in pain, and told her that if he have solved the epitaph, he would have saved her. In the morning, she told Battler to escape the island using the motor boat, and was asked by Battler why she isn't coming with him. Sayo, (acting like Beatrice), says that she was the master of the Golden Land so she cannot leave. She insisted Battler to hurry up because she might bring up a storm again if she was in bad mood. Just when she thought that Battler is already leaving, he suddenly carried Sayo and told her that he'll take her as a souvenir from the Golden Land and is gonna kidnap her which made Sayo lost in words and cried. While they are on the boat, he told Battler to close his eyes because she would kiss him. The moment she did it, the embarrased Battler opened his eyes but was slapped by Sayo, telling her that he has no delicacy and to continue to close his eyes. The last kiss was on his earlobe, which made Battler extremely embarrassed, but didn't open his eyes because he knows that Sayo will get angry. When he opened his eyes again, Sayo was no longer there. She throws herself into the sea with a gold ingot tied to her foot to weigh her down. Battler tries to save her, but washes up onto shore instead. Beatrice thus gives her life to keep the cat box of her life closed.
Battler then wanders the mountains of Nijima till he is found on the road by Ikuko Hachijo. He suffered amnesia because he was hit by a car. When he was asked about his name, he doesn't know but he only remembers the number 18, which Ikuko though that it was his age. So she gave him the name "Tohya", (which means eighteen) until he remember who he is and was taken care by Ikuko for a long time. It is also implied that only he survived and Beatrice's fate is left unknown though she did most likely die in her suicide attempt.
Eva was another survivor and was later found by the police in the Kuwadorian mansion, which is located two kilometers from the main mansion and where the explosion took place. It is also stated in the novels that she had gold bars with her as well. When asked by the police of the events that took place she refused to speak and as a result, was believed by the public to have been the culprit. She also adopts Ange Ushiromiya, the only member that was unable to attend the family conference that year. Later on, various talk shows, magazines, and even Ange slander her as the culprit. Despite her refusal to reveal the truth even to her niece, she decides nevertheless to write it in a diary.
In 1998, after Eva's death, her diary was later found by a nurse in the hospital. Ikuko comes into possession of Eva's diary, and calls a press conference to open it and finally determine the true events of Rokkenjima. She has a change of heart at the last second, feeling that opening the diary would be disgraceful to the dead. Interest in Rokkenjima does not die out, but undergoes a decline and never again reaches the same level of interest.