Superstar From Age 0 - Chapter 612:

Because her appearance was not breathtaking, the Emperor breaks off their engagement and bestows her instead to the bloodthirsty, ruthless, and cold-blooded Second Prince (Wang Ye).

On her wedding night comes endless humiliation, the genuine Princess Consort becoming a deserted women. A foolish woman before rebirth, she no longer expects his love. In this world, she must possess enough talent to awe those around her, carrying herself with composure and articulating with beautiful diction, override above the nine night.

- Description from Novelupdates

I, Hyoudou Issei, am a 2nd Year High school student and my age is equal to the number of years I haven’t had a girlfriend. And, someone like me got a girlfriend! I’m sorry buddies, I will walk the path of becoming an adult before you guys! – That’s how it was supposed to be, but why did I get killed by my girlfriend!? I still haven’t done anything yet! Are there no Gods in this World!? And, the person who saved me is the most beautiful girl in my school, Rias Gremory-senpai. I learned the shocking truth from her who isn’t a God but a Devil. “You have reincarnated as a Devil! Work for me!” Lured by Senpai’s breasts and treats, my life as a reincarnated Devil began. So the “Academy×Love Comedy×Battle Fantasy” starts here with just aggressive and worldly desires!

After rebirth, Long Xiaoyuan went into raptures because he was in poor health in his previous life. However, he suddenly found that his soul was in the body of a fatuous and self-indulgent emperor.

This fatuous emperor put sycophants in important positions while executed the faithful and the upright!

This merciless emperor married the son of a general and kept torturing him!

How could he be reborn as such a person?

The empress was pretty handsome and smart. Since the former soul of the emperor didn’t cherish such an excellent man, Long Xiaoyuan would love the guy and save himself by the way!

their example, leading to continuous warfare! However, the aboriginal people of this otherworld who have been blinded by the aesthetics of violence! Rightnow! And in the future! Let me teach you what kind of mecha represents the romance of a man! Let me show you what kind of propulsion is the iron torrent! Let me instruct you what kind of weapon is the deterrence for peace (implied by “nuclear” here)! Let me! Teach you! What exactly is the air-to-ground cluster offensive and the all-round air, sea, and land strike!! Gentlemen! I, indeed, love war! But what I love even more is to stop war with war and bring about a prosperous future where the whole world is unified for thousands of generations! Unite all nations and subdue all races! When the whole world is united as one, it will last forever...