Emperor Huizhong/ Ta-hwan/ Togon was recorded to have three empresses during his lifetime:
- Danashri/Tanashiri was his first empress
- Bayan Khutugh his second empress
- Empress Qi, his third empress
Empress Qi was his imperial concubine since Danashri’s empress years and it was said that Danashri used to torture Qi and even banished her out of the palace. Then, Tangqishi/Dangkise caused a rebellion and the whole family was purged by Bayan/ Baek Ahn. Danashri was also killed although she was said to be unaware of the rebellion caused by her brother initially, but she hid Talahai/Tapjahae from being punished…so that might be the reason why she was killed.
Togon wanted to make Qi as his primary empress after Danashri died, but Bayan opposed his decision. In order to reward Bayan and to secure his loyalty towards the country, Togon promoted him to Councillor (just like El Temur/Yeon-chul) and chose a girl from Bayan’s clan to be made his primary empress. The girl was Bayan Khutugh and Qi was made the secondary empress. After Bayan Khutugh’s death, Empress Qi was made the primary empress. Qi had more power in the court since she’s the Crown Prince’s mother.
Since Bayan’s niece was mentioned, I think the writers will make Bayan Khutugh as the niece.