(reading behind the lines)
.she used her own son for her own greed.....well too many concubines and she had lost power and the previous emperor favorism...so she did what she did ,she got pregnant too believing she would be powerful empress again and ,ML opened her belly himself to remove the fetus and that's the reason she gives to all of his concubines that "herbal tea" so they cant get pregnant

So his first time killing was his mom? And can someone remind me why he hated the imae again?