After the Demon King Is Reincarnated, He Still Wants to Conquer the World

I, Sithis, am the strongest half-finished demon king in the history of the demon clan. In order to protect my sister, I refused the Demon King's ritual, but at the cost of losing my strength, I ended up being pierced through the heart by a female warrior's sword. I thought this was my end, but... I was reincarnated in Tokyo and grew up to be an ordinary high school student. Then, what is called a brave man also came to this world, and he was still my neighbor. What do you mean, the naughty girl next to me is my sister in my previous life. What is the Student Council President? He was one of the four most powerful demon generals under me in my previous life. What does it mean that this world is actually not ordinary, the Abnormal Situation Administration, dimensional rifts, and alien monsters have appeared one after another. Wait, my grand plan to conquer the world has not been shattered yet, I will continue to conquer the world. Romantic Comedy+Fantasy Battle+Special Daily Life