Naze Boku no Sekai wo Dare mo Oboeteinainoka? - Volume 2 Chapter 2

[ 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.

How can there be any invincibility?

How can there be any Xeon undefeated?

No one in this world can be eternally number one, anyone can be defeated.

including me.

I’ve been waiting for that one person to show up, beat me, tell me that my way is wrong.

It’s a pity that that person hasn’t come yet.

…

False martial arts: strengthen yourself, break the limits of the human body, and resist bullets with flesh and blood.

Real martial arts: use the magnetic field of life to dominate the magnetic field of the stars, use the small universe of the human body to attract the power of the big universe, travel the starry sky, and smash the planet.

- Description from novelbuddy

At 18, Alex Kain is whisked away to Eryndor, a game-like realm where he gains 'Skill Synthesis', a talent to fuse skills into godlike powers. Battling monsters and conquering dungeons, he builds a harem of strong women drawn to his might and charm. With the power to return to Earth bearing incredible resources, Alex faces a growing threat that endangers both worlds in this epic of adventure, romance, and ambition.

A black pearl brought Jiang Feng from a doomsday stage where top masters with one emperor, two emperors, three emperors, four deities, and seven peerless cities show off their glory to parallel time and space, and this time and space-the end of the world has not yet opened! !! Under the sky, the youth look up, if I have strength, can I get through … these two time and space! !!

- Description from 69shu