Possibly the Greatest Alchemist of All Time

Takumi Iruma, a salaryman going on 40, is summoned to another world by accident. Unable to return him to his world, the Goddess Nolyn asks him to try living as a 17-year old boy in her fantasy world of Mildgard. Takumi is set loose on the world, and once he rescues a young girl from a monster, he starts his new life in a quiet village.

Maple, the spider monster that Takumi meets in the forest and Tames, possesses the Skill to create Spider Silk, an extreme luxury good! The silk becomes a hit amongst the villagers, and they welcome Takumi and his unique Skills as he grows accustomed to life in the village.

In order to create 100 of the toilets equipped with a magic device that Papek begged him for, Takumi visits the Mulan Company to procure help. After requesting "someone to the manage the mansion" and "someone capable of fighting and protecting me", Takumi meets a beautiful human girl, Maria, and a beautiful elf, Sofia.

Takumi informs Maria and Sofia that he'd like to travel, so he registers them both with the Adventurer's Guild and forms an official party. After Takumi sends some of the guild's troublemakers packing, he's approached by the Guild Master and advised to quickly rank up his party, so the three head out together on a Quest to defeat goblins.

Takumi wants to upgrade their gear for their journey, so he seeks out mythril and admantite ores. After consulting with the Adventurer's Guild, he accepts Quests to defeat monsters, gather Treant Wood, and escort a miner to excavate the ores. He plans to set out in three days time with the blacksmith, Dgambo.

Word of Takumi's Purification magic device has reached the Holy Empire of Sidonia, and they demand that the Kingdom of Barcula hand over Takumi, but they refuse.