Manga Koukyuu Days - Shichi Kuni Monogatari

From Day of the River: Hisui, who works for the Golden Rooster Theatre Group, was orphaned when her parents were killed in a giant massacre ten years ago and her brother Kohaku was abducted. One day, she is summoned to the Emperor's palace and only agrees to go because she suspects that he is behind her brother's disappearance. Inspired by "The Story of Saiunkoku".

From Baka: Hisui, a crossdresser dancer who works for the Golden Rooster Theatre Group, was orphaned when her parents were killed by a group of bandits ten years ago and her brother Kohaku was abducted. When the group performed in the capital, she met with the Emperor who looks like her missing brother. He suddenly summoned her to the imperial palace. Could the Emperor possibly be her long lost brother?!