Rebirth*****

Find a Novel in Which the Protagonist Makes Alchemy

After a long time, it seems that the protagonist has mastered some kind of elixir, and then the owner of this world came out and said that if he eats it, he will be like me and become a world. The male protagonist seems not to be reluctant to leave his family and friends. He has no food certificate and throws it away without food. Please give me the title of the book.