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.

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.

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.