The series was directed by Noriyuki Abe based on the series composition by Hiroyuki Yoshino, who wrote most of the scripts.
Anime Limited announced their acquisition of the third season of Black Butler with Book of Circus back in May 2016 and they’ve had a few dates for it since then.
Initially looking at a fourth quarter release last year, it was set for a February 27th, 2017 release back in November.