G-Hard

Shinichi Yamada, who came from Tokyo to a rural orphanage, discovers a crashed Cessna plane in the mountains with his friends. A suitcase full of money and guns is also found there, and one of his friends takes the money and buys a car. However, members of the secret organization "G," who own the suitcase, appear and attack not only his friend but also the orphanage. Just when it seems there is no way to stop this group that commits murder without hesitation, Shinichi reveals his true nature. Shinichi is a former member of the secret organization "G," and with his trained movements, he takes down the members of "G." This is an action manga about a man raised by a secret organization.

(Source: Kodansha, translated)