We've All Traveled Through Time, What's Wrong with Being a Little More Arrogant?

My name is Ning Xiao, arrogant Xiao. I am the cancer of the imperial court, the confidence of the people, and the natural enemy of foreigners. He is also the dream lover of girls. What? Savior? Of course I'm not! I just want to get rid of everyone who makes me unhappy. The sky is big and the earth is big, I am the happiest! Parallel time and space, fictional history + semi-fictional Red Mansion (some characters and ages have been modified)