Demon Sword Maiden - Volume 1, Chapter 80 – Nanako’s Samurai Heart

I am Master Siwei, and I speak for arcane arts.
This is an era of heroes and heroines.
This is an era of great changes.
In the end, it will be an arcane era opened by me.

- Description from Novelupdates

Kubei was just an ordinary pencil and button pusher working a day job, hating his boss and making horrible speeches when one day he fell asleep after pushing an all-nighter. When he woke up, he was bound to a chair, facing three creepy robed women and in a body way too young and way too weak to be his own. As he slowly came to, he realized that he was no longer in the same universe as he was before. He had teleported to the Kingdom of Helius, where an all-powerful church rules its lands and wages war against the elusive group known only as Mages. Armed with an incredibly cocky neural interface that just won’t shut up and his own sheer wit, our MC will find himself not just fighting to survive, but maybe even something bigger than himself.

Three centuries ago, reality tore open and parasites from another dimension poured through. They didn't just kill humanity—they consumed it, wearing human faces while spreading like a plague through every major city.The strong became Originals, commanding lesser generations in a hierarchy of monsters that humanity calls Bloodsuckers.Now they own everything. Governments, corporations, entire cities bow to creatures that should be myths.That's when the Shadowguard was born. They were humanity's elite hunters equiped with the skills and tools to put an end to the bloodsuckers. But they became nothing more than political tools, protecting the wealthy while the poor got harvested by Bloodsuckers like cattle.Kaine Cross was one of the best hunters alive until he walked away from the corruption. He decided to become a solo hunter.Unfortunately, going freelance got him killed by the very monsters he'd spent twelve years learning to destroy.Death was supposed to be final. Instead, Kaine awakens in an ancient tomb with a system that makes him something the bloodsuckers have never faced—a predator that grows stronger with every kill, commands armies of the dead, and turns their own kind against them.Every kill feeds his strength. Every corpse becomes a loyal soldier. Every battle expands his growing army until even vampire lords will bow or join his ranks permanently.[LEGENDARY WEAPON ACQUIRED: SOUL END - THE DEATH REAPER][SKILL UNLOCKED: CORPSE DOMINATION - UNLIMITED ARMY CAPACITY][MORTAL ESSENCE SYSTEM: ABSORB POWER FROM EVERY KILL]Zombies. Liches. Reapers. Wights. Revenants. And even monster girls; beautiful, deadly creatures once enslaved by the vampires now serve at his side, bound by Kaine’s will or by lust, vengeance, and freedom.He's not a hero. Heroes save people. Kaine Cross collects enemies and turns them into allies, whether they want to be or not.The vampires ruled through fear for centuries. Now they're about to learn what happens when death itself holds a grudge.Join Kaine as he builds an unstoppable army of undead and monster girls, and leads them on a path of blood-soaked revenge.Build an army. Claim your revenge. Rule the dead.

In the past life, he was an aerodynamic engineer of a well-known company, and in this life, he is a college student of a famous school.

When the two identities are perfectly integrated, what sparks will appear.

His life experience is also slowly uncovering the mystery, whether he can beat the tycoons of this era, and whether he can stand at the peak of world business.

- Description from novelbuddy