MTL - Honkai Q&A, Starting with Kiana - Chapter 259

I exist in the darkness, disappear under the bright light, and will eventually devour the sun and turn into the shadow of all things… Known by people as the indescribable terror of darkness; the king of shadows; the dark day; the existence of the shadow of the world , is still just a somewhat special high school student, facing a weird death game…

- Description from novelbuddy

"The boy has no powers," they claimed.

His name was Brayden Neal, and he was an ordinary citizen. At eighteen years old, he was bestowed the title of a king!

After ten years of fighting in the northern borders outside the kingdom, he finally returned home. He swore to kill three people the moment he arrived at the capital…

When Su Yaya awakened, she found herself in a novel world as the CEO’s Substitute Wife–-a mere cannon fodder. Knowing that divorce and a tragic ending was awaiting her once her look-alike, the President’s first love returns, Su Yaya only trusted one thing: Money.