I Secretly Develop Myself In The Demon World - Chapter 96 - 88: The Secret of the Game

“For those who dare call themselves gods, I, Wen Ran, will crush their legacy beneath my feet. Even dogs are more honorable than those filthy bastards!”A feared Godslayer, who, due to betrayal, perished under the might of the heavens, having his world destroyed. Saved by a mysterious system, Wen Ran was granted a second chance at life but reincarnated in the body of a lowly slave. Hunted by the gods who sought his head, Wen Ran vowed to reclaim his title by showing heaven his vengeance as a 'God Slayer.'

He was the continent’s strongest and most revered alchemist, Ye Zifeng. He was under one person and above millions. However, due to an unpredictable event, he had died. After his rebirth, he had become the supertrash of the Ye family and suffered disgrace. To make matters worse, he had an argument with his fiancé that led to the break off of his engagement. In this second life, he will work to change his own destiny. He vows to return to the peak of the world, trample on those who laughed at him and rewrite his legacy!

- Description from Novelupdates

The male student, Fukai Nagamasa, ignores his studies for college entrance exams in favor of following the path to chuunibyou. As he fainted during night cramming session before the exams, he realized that he was transported to a parallel world as a feudal lord in the Sengoku Era. Not to mention that suddenly, he was marrying the sixth Demon King, Oda Nobunaga’s little sister, the one who was purported to be an unrivaled beauty?