Shiin Clan

The Shiin Clan was a small shinobi clan from the Land of the Rice Fields, where Orochimaru established the Land of Sound. Despite their size, they had high ideals. After Otogakure was founded, all the skilled members joined Otogakure. But when the requests from the daimyō stopped coming, their leader lost his reason to live and set sight for a gold mine. He and the clan members attacked the village next to the mine, but something went wrong and the clan members started to kill the villagers. Menma panicked and tried to escape, but ended up falling off a cliff and losing his memory. He was later saved by Naruto.

Tattoo
The members had a special tattoo on the right upper arm, with the appearance of a purple band circling the arm three times. The tattoo was only visible when the wearer was perspiring.