Valkyrie's Shadow - Before the STor

Time is an illusion, and reality is a fragile thread in Kael's fractured world.Kael's life is defined by darkness, memories that flicker in and out like glitching shadows. Struggling with haunting nightmares and terrifying hallucinations, he finds himself trapped in a reality that doesn’t make sense—a reality where time is breaking, and nothing is as it seems.When a mysterious red notebook, filled with cryptic symbols, falls into his hands, it opens a gateway to a world where the laws of time no longer apply. Every hour, every minute, every second twists and warps, and Kael begins to realize that something—or someone—is manipulating time itself, pushing him to the edge of his sanity.But he's not alone. A girl, whose existence is as twisted as the world around them, seems to be connected to his suffering. Kael's bond with her grows as they both search for the truth behind their disturbing experiences, yet the more they uncover, the deeper they fall into an abyss of despair and madness.The Pulse, an unfathomable force that distorts time and reality, pulses through their very existence. As Kael inches closer to the truth, he faces a devastating choice—one that could either save them or shatter everything they hold dear.Time is collapsing, the Pulse is awakening, and Kael must confront the horrors lurking in the fractured timeline before it consumes them all.

She, a renowned assassin of the 21st century, actually crossed over to become Su Manor’s most useless good-for-nothing Fourth Miss.

An accident gave Ye Han a magical ability to see through. Since then, his life has become rich and colorful. He has developed the strongest business empire, dominated the gambling world, and rejuvenated his medical skills. He has become a master of medicine and Taoism. The goddesses rushed towards him one after another. As a man, and a limited edition man, Ye Han was under a lot of pressure and had to go on an exploration with a few tomb robbers. However, a shocking secret from ancient times to the present gradually emerged. in front of him!

- Description from novelbuddy

Kuramoto Daisuke, a freshman in High School was suddenly exposed to someone vanishing in front of him. Turns out he was admitted to a Special Class full of Isekai Heroes that were regularly summoned to Otherworlds since the start of their Middle School. He was told that he was to become their Support to prevent each of the Heroes' fate of dying in the world they were summoned into. Though mediocre, he realized that his ability has a great potential but it needs a lot of hard work on his part.

Unconvinced of being just the Support Character, he vowed to excavate his mediocre ability, all the while supporting the Heroes using it.

And maybe more.