- Acting for Two: Ciel's English dub voice actress Brina Palencia also voices his mother, Rachel Phantomhive. Averted in the Japanese version, however, where Ciel and his mother are portrayed by different voice actresses.
- Actor Allusion:
- Fake Brit: In the English dub, the actors are all American, mostly Texan. In J. Michael Tatum's case, it comes from a lifetime of watching Doctor Who and other British shows, and a British speech therapist when he was a child, who he speaks of a lot at conventions. This trope gets a humorous nod in the "Making of Black Butler II" OVA, although some of the Animated Actors are just faking different kinds of British accents.
- Fan Nickname: After the introduction of what seemed to be the real Ciel, some fans tried to avoid confusion by calling the boy the manga follows "Astre." It came from "Astre" being a Development Gag to a potential name for Ciel and how it would pair with "Ciel" for Stellar Theme Twin Naming. An alternative to "Astre" has been to simply refer to the boy the manga follows as "our Ciel" and the twin as "real Ciel"
- I Knew It!:
- A vocal minority of fans spent much time attempting to reassure the rest of the fandom that A-1 were trolling the fanbase and that Ciel and Sebastian would return in full capacity, despite the announcement of the new master and butler. Guess what happened when episode 1 aired?
- Some fans were guessing that Alois was cross-dressing to meet Ciel after a preview for episode five. They were right.
- In the murder mystery arc in the manga, a lot of people speculated that Sebastian was not really dead; they were right. Some others also speculated that a snake would be used to commit one or more of the murders; they were also right.
- One person on this site's WMG page predicted that if Ciel gave up on revenge, he'd be breaking the contract, and Sebastian would be free to devour his soul.
- One fan theory speculated that the Shinigami were all once humans who committed suicide and now must atone for it. This is confirmed in chapter 105.
- A lot of theorists speculated that Ciel had an elder twin brother who was sacrificed to summon Sebastian and that said twin was the original Ciel Phantomhive. His appearance in Chapter 129 confirmed this.
- Ciel having experienced Rape as Backstory during his month-long imprisonment was speculated for a long time before chapter 135 confirmed it, though most fans who guessed it weren't exactly happy about it...
- Name's the Same:
- Sebastian Michaelis, Master Tea Blender of Tetley Tea. They insured his taste buds for £1 million. He also shares his name with an actual priest who wrote a book on demon hierarchy.
- Don't confuse Joker from the Circus arc with the other Joker.
- Nor should you confuse Ronald Knox the Grim Reaper with Ronald Knox the Catholic priest and detective fiction author.
- Playing Against Type: John Swasey as a Bishōnen. instead of his usual roles as either a Cool Old Guy, Middle-aged men, or Evil Old Folks.
- Relationship Voice Actor:
- Sebastian and Lau are Arthur and Renzo and Silver and Shadow.
- Grell and Claude are Lelouch and Suzaku, Yata and Kusanagi and Ichimatsu and Osomatsu.
- Sebastian and Grell are Kuroh and Yata, Jun and Souta, Shizuo and Shinra and Jyushimatsu and Ichimatsu.
- Sebastian and Finnian are Shizuo and Walker and Erwin and Eren.
- Grell and Dagger are Yukio and Rin and Koro-Sensei and Karma.
- Dagger and Beast worked together before as Ivan and Agnes. Ciel and Alois also had minor appearances.
- Sebastian and Viscount Druitt are Midorima and Takao and Dolor and Ban. In the same vein, quite a lot of voice actors meet in the latter such as:
- The Wiki Rule: Kuroshitsuji Wiki
Trivia / Black Butler