AKKI NO KOUKYUU KAEN

Akki no Koukyuu Kaen summary:

Hu Linghua is the "evil lady" that everyone fears. Her true identity is the complete opposite of an evil woman, with a lovely face and pure personality. It was supposed to be something no one knew about…. Until she received a secret order from Crown Prince Sun Bailian. Receiving the order to "become my consort and brother," Linghua begins a double life as both the "favored consort" and the "brother" of the crown prince...?!