Circus Kitan

"The Great Dark Circus descends from a rotten, cursed, demon-related lineage. Every sin, every flaw and every torment from men are represented in our show.

Come and watch, meet the tragedy of the ventriloquist mother, the secret of the butterfly princess and the angst of the mist-man...

Going into the roaming black tent of the Great Dark Circus is acceding to the magic of its phenomena, and that magic will be the source of our misfortune, because we are all of them."

Source: My Anime List