Turning Antagonist to Protagonist: He is Both Soft and Fierce - Chapter 123 - 118: Sister-in-law, You’re So Fair-Skinned

The whole world is subjected to a highly dangerous standardised exam called the Global Examination. Answering questions by putting their lives at stake, they would live if they passed the test. Every month the exam will undergo reformation while, occasionally, it is random.

He is a young man without a spirit root. It is believed that this denies him the chance at cultivation. However, a mysterious lady imparts a Supreme Demon Classic to him and from then on, he starts his path of cultivation.
He undergoes a total transformation to emerge as the most fearsome and powerful fiendish demon in his era, that even immortals and fiends are fearful of him, and saints are at his beck and call.
Mastering the Supreme Demon Classic is the turning point in his life. He is able to unleash his immense and divine power from within, illuminating the entire universe!

- Description from Novelupdates

James, a brilliant mechanical engineer and passionate history enthusiast, loses his life in a tragic house fire—only to find himself in a mysterious world as the ruler of an island nation. Armed with his modern knowledge and unwavering ambition, James embarks on a bold mission to industrialize his kingdom and build an empire on which the sun never sets.