Yorukumo

Yorukumo (よるくも) is a manga series by Michi Urushibara. It was serialized in Ikki.

Plot
The World consist of the upper, the middle, and lower classes.

Those who are wealthy live in the Town. Those who are poor live in the Fields. Those below, in the thick and gloomy Forest....

In the Fields, Takaoku Resturant's show girl, Kiyoko, supports her mother by managing the food preparation. One day, a regular patron named Tanaka, who recruits day labourers for the underground, requests that they bring meals to an assassin from the Forest called "Yorukumo," or "Night Spider."

Yorukumo was born in the Forest as a disposable child, raised to be void of emotions, unable to feel pain, and without knowledge of reading and writing. With Tanaka's instructions, he easily handles assassin jobs daily. When Kiyoku and Yorukumo meet, the World begins to come apart a little at a time.