MTL - Peak Strength - v4 Chapter 266 Superiority

Kurono Maou is a high school student who is sensitive of his sharp eyes and bad expression. No girlfriend but gifted with friends in his own way, he had been living a peaceful life.

[ Fusion Successful ][ Water Toad + Sky Dragonfly + Nightmare Moth + Bluefang Hyena= Nightmare Hydra ]----Yuki Igarashi, once a terminally ill boy confined to a hospital bed, dies with a silent wish for strength and freedom.That wish is mysteriously granted when he reincarnates into a fantastical new world. Not as a human, but as a newborn Frost Dragon.With his memories intact and curiosity alive, he is soon greeted by a mysterious system called the Dragon God System, which mistakenly binds itself to him, claiming he is not its original host. Still, it is now eternally bound to him.Despite his infant form and weak body, Yuki discovers he can extract bloodlines and skills from other creatures using the Dragon God Codex, and fuse them within a mysterious space called the Fusion Lab.Even more shocking, a glitch in the system allows him to repeatedly Fuse bloodlines without depleting them, opening the door to limitless growth.

As a promise, he went out into the world as an assassin. 3 years later, after becoming the Supreme Assassin, he gave up on everything he had and returned to the ranks of ordinary people. But one day, Kismet, a mystical game created by the National Research and Development had appeared.

Enigmatic hands, spectral frame, and one cunning strike just like the swing of the Grim Reaper. The Supreme Assassin takes on the mystical world, and how his legendary tales sets off, progressively ascending the altar to becoming the best.

- Description from Novelupdates

As the era of dragons gradually came to an end, as arcane masters left countless riches and legends under the starry sky, one awakened youngster after another began to set foot on their journey.