The Tenshouin Naraku is a secret assassination group founded by Utsuro that works behind the scenes for the Bakufu government of the Gintama world. They consist of lawless people or orphans that were thrown out from society and were taken in by the group and trained. The Naraku has been known so far to been the most common enemy force that Gintoki and his allies have fought against starting from the Courtesan of a Nation Arc.