The Butler, Applauding is Chapter 143 of the Kuroshitsuji manga.
Elizabeth confirms that Ciel had lied to everyone for the last few years. Upon hearing her words, Sebastian concludes that Elizabeth did not return home as she was reunited with her true fiancé. Then, Edward steps forward and demands to know why Elizabeth did not tell anyone about "Ciel" and why "Ciel" did not return earlier. "Ciel" answers that he was unable to come home until now and only managed to finally do it thanks to Elizabeth.
Alexis is still confused about the matter and wants to know what exactly happened and why it could even come so far as he is, after all, the guardian of the Earl of Phantomhive. "Ciel" is willing to explain everything to him, but before he can, a Scotland Yard officer runs out of an adjourning room, holding a Vega blood vial. He presents it to everyone and announces that they found numerous of these vials in the manor's basement and that the vials are the same as the ones secured in the Sphere Music Hall. This information shocks everyone, and right afterward, more police officers arrive, dragging an annoyed Blavat Sky with them.
Taking everything that happened and everything he found out into account, Ciel deduces that the Sphere Music Hall's cult leader, the Blue Star Sirius, is nobody else but his twin. At the same time, Fred Abberline asks Blavat if he is the cult's leader, but Blavat says that he is merely "stardust" and a missionary to Lord Sirius who is infinitely more valuable than he will ever be—or anyone who lost their life prolonging Sirius', Ciel Phantomhive's.
Everyone is shocked when Blavat addresses Ciel as the Blue Star, especially Ciel himself. Sebastian tells him that everything is going according to "Ciel"'s plan and that they were played all along.
The police officers address the matter of why Ciel opened his own music hall opposing the Sphere Music Hall if the latter one is supposed to be his as well. Edward interferes and says that the Funtom Music Hall did not engage in any criminal business, and promptly learns that the number of victims in London has only increased after the Funtom Music Hall opened. Fred wants to explain the Funtom Music Hall's existence but remembers in the last second that low-ranking officers do not know about the Queen's Watchdog. Then, begrudgingly, Fred has no other choice but to take "Mr Phantomhive" to Scotland Yard as the prime suspect in the Sphere Music Hall serial murders.