Black Rabbit is a character from the anime titled Mondaiji tachi ga Kuru Kara Isekai So Desu yo? (such a long title), she is a girl who has the ears of a rabbit, she has light blue hair with two long bunny ears on top. Her hair will turns pink when using a great power, just like what you can see in this Black Rabbit Cosplay. she cute in pink isn't she ^^.
in this Black Rabbit Cosplay picture Yonor cosplaying as Black Rabbit when she was in a state of full power, because I don't watch this anime so don't ask me how fit Yonor as Black Rabbit here, all I know is that she looks so sweet and cute in this Black Rabbit Cosplay picture.