MTL - My Wife Is A Princess - v3 Chapter 291 Sister-in-law

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

You had taken up the Student profession

You had now reached level 7.

Acquired skills: elementary school knowledge, junior school knowledge, and senior high school knowledge.

You took the university entrance exam and scored full marks.

Your have been upgraded to level 9, and you have activated the profession-change interface.

You became a scientist and gained R&D skills.

You used R&D skills and gained space fortress-building technology.

You used R&D skills and gained starship technology.

You are now invincible.

Maid, older sister, younger sister, and even mother, all of them.

Han Sheng Li is the Crown Prince of the Great Han kingdom. Since the age of fourteen, he mostly went to the wars with his father, Han Wenji, the great emperor of the Han Kingdom. He's the most favored child of his father but, is the cruelest and ruthless among all of his seven half brothers.