Baka to Test to Shoukanjuu‎ - Volume 5, The Seventh Question

A striking man of mysterious origin and peerless talent, he looks back at the world, in all its entirety, with utter disdain. And yet, in the treacherous and unpredictable ultimate formation of the Boundless Secular World, he guards a breathtaking ancient qin with broken strings, waiting silently for the destined one to arrive!

A boy encounters him, and knows for the first time that the world beneath the Heavens is a fickle place. Not even demons, devils, ghosts and monsters can match the frivolity of human nature!

A slender physique, and jade-like beauty, but the sword that strikes between heaven and earth is not unlike a streaming rainbow!

The vastness of the starry sky, the seven emotions and six desires! Greed, anger and ignorance! The teachings of Buddha will grant you boundless strength!

A sea of blood will come, at the cost of all mortal beings full of honest hope!

The ghosts wail as the gods roar, but the sea of blood has no end!

Where, pray tell, is the path I should take?

Since there is no path, no matter how bitter and bloody the sea, even if my boat is made out of bones, I will soar to the heavens above!

- Description from Novelupdates

An Individual from Earth finds themselves in the Shinobi World, equipped with a Scientific System. From that moment, he delved into scientific research far ahead of its time.

In a world where power is hidden behind corporate empires and ancient martial legacies, John Lopez lives a double life. Known publicly as a carefree young man, he secretly bears the terrifying title of the King of Horizon, a supreme martial expert feared across the continent.When his beloved sister Queenie becomes the target of a brutal smear campaign threatening to destroy her company and reputation, John is forced to confront the shadows lurking in the high towers of business and politics. As conspiracies deepen and enemies rise—ranging from corrupt business moguls to deadly assassins—John’s wrath becomes unstoppable. But danger isn't only around him—it strikes home when his eldest sister, Alice, falls victim to a rare and deadly poison. With time running out, John must defy the odds, wield ancient techniques, and unleash the full fury of Horizon’s might to protect his family.

All I ever wanted was for famous detectives like Sherlock Holmes or Arsène Lupin to appear in my dreams and share their wisdom. But instead, why am I hearing the voices of notorious serial killers in my head, guiding me to solve a string of mysterious cases?