Gintoki Sakata (坂田銀時, Sakata Gintoki?) is a fictional character and main protagonist of the manga and anime series Gintama, created by Hideaki Sorachi. A former rebel samurai who lives in a fictionalized version of 1860s Japan after being invaded and transformed by aliens, he fought the invaders until he realized the lack of sense in doing so, leading to him choosing to instead make a living as a freelancer for hire in Edo.

Source: Wikipedia