Start year: 2006
Issues in volume: 6
Proper Japanese Title: 蒼黒の餓狼 北斗の拳レイ外伝 (Sōkoku no Garō - Hokuto no Ken: Rei Gaiden)Also Known As: Fist of the North Star - Rei Side Story: Bloody Wolf's Darkness BlueOriginally serialized in Weekly Comic Bunch.
Publisher: Shinchosha
Issues in this volume: