An organization called "Agency D" was created in the fall of 1937 as an independent army unit on the personal initiative of Lieutenant Colonel Yuki. According to rumors, Yuki himself in the past was a good agent and got a lot of secrets from the enemy until he was betrayed ally. Before escaping from captivity Lieutenant Colonel brutally tortured,which explains the absence of the left hand and the fact that he walks with a cane, limping on his left leg. Having received the nickname of "Lord of Darkness", Yuki teaches soldiers on principles that are very different from the traditional military wisdom. Ignoring the military ranks, clothes and behavior, he teaches his players to be invisible and unseen,and takes candidates from afar, training specialists several languages, hacking skills and stealth. Under the false guises of his agents perform missions around the world.