Flash Marriage: The Prince's Contract Wife - Chapter 542

Yuki, a high school junior, dies heroically saving a stranger and is reincarnated in a fantasy world, where he discovers an extraordinary and unrivaled power.

A great demon king who came from another world to conquer Earth. To save the Earth, Li Luyou could only first take care of this great demon king… a little girl proclaiming herself Her Imperial Princess.

- Description from Novelupdates

Sylas Gray returns to his hometown in the countryside for a winter vacation to his ancestral home, only to find himself caught in the midst of an apocalyptic outbreak. The world descends into chaos as the undead overrun everything, and the small town he grew up in is no exception.With hope dwindling and death lurking around every corner, Sylas witnesses unspeakable horrors—brutal killings, betrayals, and the darker side of human nature. Yet, amidst the despair, Sylas refuses to give up. Determined to escape the town and reach the capital, he is thrust into a shocking revelation.A mysterious change occurs within him, granting Sylas the ability to sense and control space. He discovers that he possesses a pocket of space within his own body—a power that could be his key to survival.Follow Sylas as he embarks on a perilous journey, fighting to survive, uncovering the truth behind the apocalypse, and discovering the true potential of his newfound abilities.