"I'm the Demon King, but for Some Reason I Became the Princess's Guard Knight"

My name is Kuroma Shiroma, the strongest Demon King of all time. To escape from my little sister and the yandera guys of the Demon King's Army's Four Heavenly Kings, I accidentally used the ultimate form of transfer magic—interdimensional transfer magic—and when I came to, I was in the body of a female knight!? Moreover, I'm a member of the Imperial Guard directly under the princess? And on top of that, the royal palace is full of enemies because of the succession struggle for the throne? There's supposedly a hero and a Demon King, but that's not even the issue right now. The succession struggle is one thing, but some princes or whoever are making moves on me and it's dangerous. But you know, that's all trivial stuff. I'm the strongest Demon King of all time, and all the members of the knight order are women. It's a harem. The captain, vice-captain, maid chief—they're all beauties. I won! I've already won. The victory was decided before the battle even started. The real problem is my little sister and those Four Heavenly Kings—they're not coming after me, right? It'll be fine, right?