Updated theory
Twilight 1
Godha killed all six (Genji key destroyed)
Twilight 2
Krauss killed Natsuhi. Faked his own death. Nanjo lied to confirm.
Twilight 3
No deaths
Twilight 4
Jess killed Shannon, Kanon disappears
(Shannon & Kanon key destroyed)
Twilight 5/6
Nanjo killed Kumasawa. Godha fakes death. Jess and Nanjo lie to confirm
Twilight 7
Godha killed Nanjo
Twilight 8
Godha killed Jessica
Not killed: Kanon, Battler, George, Maria, Godha, Krauss
Culprits: Godha, Nanjo, Jess and Krauss
Is my theory