Kyoukai Senjou no Horizon - Volume 2, Chapter 22: Replier on the Chopping Block

Read at least six chapters, then prepare to crave the rest.The main character will show up in Chapter Five, though I don't recommend skipping the first four chapters.-----The world was celebrating. The Demon King was dead, along with his Darkness Generals.Humans led the other races to war for subjugation. They killed all, and none were spared. However, thousands of years before this happened, a piece of history was altered by time itself. In fact, the Demon King didn't have four generals but only one, which he sealed and sent into eternal slumber. Just as he started to close his eyes, the chains locked away for eternity shattered into pieces.

A continuation from where High School DxD Volume 25 left off.

Ian was an ordinary guy on his way to work when he suddenly found himself in a strange and dangerous world ruled by dark races like vampires, werewolves, and demons. Transmigrated into the body of a lesser vampire, Ian must quickly adapt to his new reality where survival is a constant struggle.Just when all hope seems lost, Ian discovers he has a unique advantage: The Strongest Body Customization System, which allows him to modify and customize his body by consuming biomass. With this golden finger, Ian starts to turn the tables, designing bone claws and other enhancements to give him an edge against the terrifying werewolves and other supernatural threats.But as Ian learns more about the Curtained Imperium and the rigid hierarchies of the vampire race, he realizes that defeating his enemies is only the first step. To survive and thrive in this dark and brutal world, Ian must rise through the ranks, uncover the power of his system.Need to fly? Customize a pair of angel wings!The body is small? Add hundreds meters of height and become bigger than Godzilla!Need a weapon? Customize bone claws and kagune on the spot!