Kumoko" is the nameless main protagonist of So I'm a Spider, So What? She is reincarnated in another world in the body of a Small Lesser Taratect, a weak monster, in the largest, most dangerous dungeon known to man: the Great Elroe Labyrinth.

Her life in the labyrinth is fraught with danger, forcing her to fight and become stronger to survive. She fights, eats, levels up, and evolves continuously over two years until she becomes an Arachne and meets Ariel.