Killer: Kumasawa
Accomplices: Genji, Kanon
• Kanon delivered the letter to Maria. Either Kumasawa lied about his alibi, or he did it on the way to calling the cousins for dinner.
• Kumasawa snuck out to the mansion during the night to commit the first 6 murders. If they asked for tea at all, she could have “helped” and snuck in sleeping pills, or she could have put sleeping pills in their dinners when serving the dishes. Gohda and Shannon she could have picked off on their own (plus she has that stake-gun of hers, most likely).
The sleeping drugs would’ve been slow-acting, not taking effect until the night. Anyone who got drugged and remained alive may not have noticed since they just attributed any exhaustion they felt to the family conference.
• When Natsuhi talked to Kinzo, she actually mentioned that people were missing. Kinzo believed/thought it was the devil’s roulette, and so demands that he be taken somewhere else to help protect himself. Natsuhi takes him there, and then goes back to the study to get something else for him, or because she knows Eva will come up to check on what’s going on. Natsuhi doesn’t think anything big is going on, but she humors Kinzo. Having worked for Kinzo for so long, Kumasawa was able to figure out where Kinzo went to. She kills him at some point and throws him in the incinerator. [Or Natsuhi just randomly and conveniently hallucinated Kinzo in the room was already dead and/or gone.]
• Kumasawa, Kanon, and Genji just lied about Eva and Hideyoshi’s locked room. They got in with their keys and the cutter.
• Kumasawa follows Kanon into the basement and shoots him with the stake-gun. This could be planned, or Kumasawa could have betrayed Kanon.
• Kumasawa or Genji slipped the third envelope onto the study table when nobody else was looking.
• Kumasawa and Genji get Maria to believe the Beatrice story. They kill Nanjo, get out a Kumasawa dummy they had prepared, and then Kumasawa either kills Genji or uses a Genji dummy.
• They draw out Natsuhi with the fourth letter. Kumasawa then shoots Natsuhi with a second gun, swaps the guns, and takes the letter.
[You can make this a Kanon theory too if you add Nanjo as an accomplice. Kanon’s death scene was just an act, and Nanjo helped cover it. Then both Kumasawa and Genji could be either a dummy or actually dead.]
Killer: Kinzo
Accomplices: Natsuhi, Genji
• Shannon most likely delivered the letter. She took some time to sneak away from Kumasawa and Kanon. Kinzo probably told her it was a prank or something, and since she was in the first wave of victims, it’d be too late for her when they found out it wasn’t. Genji also could’ve helped cover for her.
• Kinzo could have had Genji put sleeping pills in their dinners when serving the dishes. Kinzo and Genji could have picked off Gohda and Shannon when they were on their own, which wasn’t that hard since they were surprised and there was the stake-gun.
• Natsuhi sneaks Kinzo out of the room that morning. Natsuhi goes back to the study afterwards since she knows Eva will come back after her.
• Natsuhi gives Kinzo the new key to the storehouse, and Kinzo dumps Klaus’s corpse (who has 6 toes too) in the incinerator. He uses the wheelbarrow to help carry the body.
Jessica isn’t there when they find Kinzo’s corpse (so we don’t see her reaction, or even if they tell her that they identified Kinzo’s corpse by the 6th toes), plus she’s in shock from Kanon’s death.
• Genji tricks Eva and Hideyoshi into opening the door for him, and then Kinzo kills them with Genji’s help. Genji leaves, and then Kinzo locks the door from the inside and hides under the bed until everyone discovers the room and opens the room.
• Kinzo shoots Kanon in the basement.
• Natsuhi is the one who put the third letter on the table.
• Kinzo convinces Maria about Beatrice, and shoots Nanjo, Genji, and Kumasawa.
• He leaves a letter for Natsuhi. When she comes out he shoots her with a second gun, switches the guns and takes the letter.
Killer: Rosa
Accomplice: Nanjo
• As soon as Rosa leaves Maria in the rain, she switches into a Beatrice costume, gives the letter to Maria, and then changes back to her regular clothes.
• She was at the family meeting—she could have drugged their tea and killed everyone else.
• Rosa’s corpse in the storehouse is actually a dummy, which Nanjo lies about.
• When Natsuhi talked to Kinzo, she actually mentioned that people were missing. Kinzo believed/thought it was the devil’s roulette, and so demands that he be taken somewhere else to help protect himself. Natsuhi takes him there, and then goes back to the study to get something else for him, or because she knows Eva will come up to check on what’s going on. (Or she’s going back, and Eva just happens to come up at that time.) Natsuhi doesn’t think anything big is going on, but she humors Kinzo.
Since Kinzo is usually holed up in his study, Rosa knows Kinzo will probably be the toughest one to get. During this time, Rosa was hiding out near Kinzo’s study—so she witnesses Natsuhi taking Kinzo to his new hiding spot, so she knows where it is and can kill him.
• Rosa somehow gets Eva to open the door for her, then kills Eva and Hideyoshi, locks the door from the inside, and hides under the bed.
• Rosa shoots Kanon in the boiler room, no biggie
• Nanjo is the one who put down the third letter
• Rosa comes and she and Nanjo kill Kumasawa and Genji. Nanjo may have been killed, may have just been a dummy.
• Natsuhi’s death is the same as the others.