Tsubame

One of the Butterfly Triplets.

They are the demon sisters that head the society in opposition to the Lotus Association. Their followers are mainly seen with black veils over their faces. They can transform into butterflies hence their name, and they usually openly display their demon powers. Their usually appear while laughing behind their fans in an "ohoho" fashion. For a certain duration of the series, they had an interest in publishing yaoi doujinshi featuring Touka.

(Source: Wikipedia)