Sebastian admits and reveals the culprit’s identity was known all along – it was Earl Grey, the Queen’s butler, whom she had sent to kill Siemens, in order to disrupt Germany’s financial stability, and at the same time, jokingly frame Ciel for the murder as a compensation for the accident with Noah’s Arc Circus. The case is considered closed, but soon, Arthur Conan Doyle notices the inconsistencies in the theory and reveals the truth. The reverend also deduces that Siemens had jokingly faked his own death, but was killed soon afterwards by another guest – Woodley, who wanted to frame Ciel to prevent him from destroying his diamond business.

Soon, it is found out that one of the murders was mistakenly done by a snake that was trained to go after Ciel’s scent, later revealed to be sent by Snake from Noah’s Arc Circus in an attempt to avenge his friends.

Sebastian had “foreseen” his murder and the letter he had sent was addressed to reverend Jeremy Rathborne, calling him to investigate.

Black butler season 2 ova 1