I'm In Love With My Bestfriend's Billionaire Fiance! - Chapter 19: Kira: Not A Complication

A skilled but unfortunate modern-day assassin was killed in a freak accident. However, he soon found himself summoned to another world by an evil wizard, who had him possess the body of a boy as an experiment. After successfully planning the evil wizard’s downfall, he used the wizard’s body as a springboard to gain influence and power in his new world.

- Description from Novelupdates

One rule: Survive. Everything else is optional.Reika Kagetsu doesn’t want to be a hero. She just wants to feel—pain, fear, adrenaline—anything to remind her she’s still alive.Tenshiko Academy promised her that.What she got instead? Brutal training. No rest. No second chances. And monsters—inside and out.Now she’s fighting the Shikiban: creatures born from blood, madness, and buried secrets. But the deeper she goes, the more she begins to wonder...What if she’s one of them?Power always comes with a price. And Reika is about to pay it in full.

This is the tale of Arin, a once kind-hearted and gentle child, now a man hardened by the cruelty of society and the brutal trials of life—a man transformed into a ruthless criminal, devoid of mercy. As his world was collapsing, fate transported him to a new realm. This world, more vicious and savage than his own, was steeped in magic and dark mysteries.Ironically, it was in this fearsome world that Arin, now an undead being, began to rediscover his lost humanity. Through battles and bloodshed, amidst the clash of sorcery and steel, he started to reclaim the compassion he once hated. This is not just a story of survival but a saga of transformation. Follow Arin’s journey as he rises to power, determined to become the ruler of this harsh world. In a twist of fate, he now seeks to save the very humanity he once wanted to destroy.