Resolved skin posted on walls

so i just binge reading to be virtuous wife and 8TT and remember this vicious female lead but forgot from which novel
1. the FL at some point targeting useless son of some general of empire
2. she kill him and posted his skin at wall to create terror
3. the brother came to investigate
4. she wore the skin to create an illusions that he is alive
5. the brother get some hallucination from some butterfly or flower to kill his imaginary brother

thats all i remember
because growing novel with female lead i had some difficulty remembering the novel
please help

 

Thousand-face Demonic Concubine at the beginning of the novel.

 

Holy smokes.

 

slowly backs away from OP

 

Thats not a nice thing to do

 

thanks
i will check later