Nigotta Hitomi no Lilianne - Chapter 9 – Twelve Months After Birth

Being able to learn any skill immediately, and just by raising its proficiency, stand at the summit.

He is the World Chef Association Honorary Chairman, having the title of the World Chef God.

He is the greatest composer, pianist, and conductor after Beethoven and Mozart.

He also has the title of Underground Racing King, Fist King, Gambling King, Giant of the Stock Exchange Market, Arm of the Industries and King of the Skies.

He who has a miraculous learning ability and can stand at the apex of all things if he so wishes for it, the Omni Genius.

- Description from Novelupdates

Just as a gamer found an overpowered skill book called ‘Item Upgrade’ in the hottest virtual reality role-playing game on Earth, something happened to the game’s system, causing his soul to leave his body and go to another dimension. Common sense dictates that he would be born anew then become the greatest overlord of this world by making use of his advanced knowledge. Not in this case! He was already dead. Only some fragments of his soul and that skill book managed to get into that dimension and merge with an ordinary common youngster called Bai Yunfei.

This was the enormous Tianhun continent, where humans could be said to have no limits. There was a group of humans here who could cultivate the power of their own souls then control their bodies, the natural elements and even other people’s souls with that power! These special beings were called — soul cultivators. Come witness how the several fragments of the dead inter-dimensional traveler’s soul and that skill book, which was not governed by the laws of this plane, were going to help Bai Yunfei become a legendary soul cultivator and craftsman!

Zavier met Cosmic Consciousness after his death. He was satisfied with every system that Cosmic Consciousness exhibited, so he wanted all of them. Surprisingly, the Cosmic Consciousness obliged him.

Zavier was reborn in an isekai full of magic and alchemy. Now, he had many routes to upgrade. Interestingly, to coordinate these systems, Cosmic Consciousness gave him the gift of being able to duplicate himself. He could clone a finite number of himself to manipulate these systems.

Magus, Alchemist, Mesmer, Tamer, Hunter, Vampire, Werewolf, Dragonknight, Necromancer.....

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By the way, it wouldn't appear NTR or some bullshit harem of courtships. MC of course will have harem but not for cliches.

Heath transmigrated to an alternate dimension and awakened the [God-like Extraction System]. With the help of the system, he steadily walked the path of the Witcher to become a god.