Darker than Black: Shikkoku no Hana
Manga
Darker than Black: Shikkoku no Hana is a Japanese manga written and illustrated by Yuji Iwahara. The series is a spin-off to the 2007 anime series Darker than Black and focuses on Hei, who is in a way to hunt the Canadian Contractor Matthew Edner, also known as a man named Harvest and the "Black Dendelion."
Description from Wikipedia, available under CC BY-SA 4.0. May be shortened.