Both MLs are fake head eunuchs who have entered the palace in order to get revenge for their family, and have a fierce reputation. Both dramas have a royal princess/empress who is obsessed with the ML.
Both MLs are pretending to be eunuchs in order to achieve their goals. Both FLs discover their secret in the opening scene, so the ML ends up taking them to the palace/taking them to his home to protect his secret.