The "Kuroshitsuji" Anime Primer
Anime
Circus? Murder? A straight-forward list of the series that comprise the "Kuroshitsuji" anime, including both manga adaptations and anime-original material.

TV, 2008,
24 eps
Me:-
Author:6
The original animated adaptation, with approximately half of the material taken from the manga and the other half original.

TV, 2010,
12 eps
Me:-
Author:4
A sequel to the first season, composed completely of original material and including characters not from the manga. Fairly divisive; if you're a manga purist, it can be skipped.

TV, 2014,
10 eps
Me:-
Author:8
The start of the arc-specific adaptations, which ignore the existence of the anime's second season and instead follow the manga.

OVA, 2015,
2 eps
Me:-
Author:7
Like Book of Circus, an adaptation of a manga arc that ignores the anime's second season.

Movie, 2017,
1 ep
Me:-
Author:-
Another manga adaptation, like Book of Circus and Book of Murder.