Raijin

and his brother Fūjin are the Legendary Stupid Brothers.

Mizuki Strikes Back arc
They are strong albeit stupid ninja from an unknown village, who are currently imprisoned in Konohagakure for killing their comrades over a meal. There they were befriended by Mizuki, who convinced them to help him escape by offering them food. Once they escaped, they fought Naruto and the members of Team 10. They were unable to beat the brothers, and it was not until Tsunade arrived and threatened to not give them any more food that they returned to jail.

Trivia

 * Raijin shares the same name with the Japanese mythological thunder god.