The Gang of Four were a group of men who served under Yomi and appeared in the Naruto: Shippūden the Movie. Kusuna was the one responsible for giving the other three their special chakra powers through the use of chakra snakes given to him by Yomi. The three fighters tend to abuse their newly enchanted chakra, using overly powerful techniques to deal with even the most minor matters, resulting in rapid drainage and requiring replenishment, which ultimately led to their downfall, as their opponents took advantage of their low chakra moment and took them all down (except Gitai, who was killed when his unstable power led him to self-destruct).
