Maybe the Empress hated the fact that the blonde maid had a sex and a kid with the emperor cuz she was in love or kind of liked her. I don't know if the maid felt the same. Cuz in one chapter the maid was looking the emperor with the eyes of someone in love.
That was my theory as well, the way the empress looks at the prince feels ''genuine'' anf the one trying to poison him would be the one jealous of the empress' adoration for the prince
Maybe the Empress hated the fact that the blonde maid had a sex and a kid with the emperor cuz she was in love or kind of liked her. I don't know if the maid felt the same. Cuz in one chapter the maid was looking the emperor with the eyes of someone in love.