Drifters is a unique series in the sense that it uses a number of real life historical characters to make up it's cast, starting with the Drifters themselves, who are these people in real life?

Shimazu Toyohisa: A member of the Shimazu clan who participated and died in the battle of Sekigahara
Oda Nobunaga: A Sengoku period general known as one of three men who unified Japan
Nasu no Yoichi: A famous samurai of the Genpei War in the late 1100s, early 1200s
Hannibal Barca and Scipio Africanus: Two underrated Roman War Generals
Butch Cassidy and the Sundance Kid: Notorious train robbers from the old West as part of the Wild Bunch Gang, Drifters chose to use a later depiction which shows them in their last days in Bolivia
Naoshi Kanno: A Japanese World War II fighter pilot
Tamon Yamaguchi: A Japanese World War II Naval Vice Admiral, sank in the Battle of Midway

So that's the Drifters, if they come round again we'll cover their enemies.