Located in the land of Water, the Hidden Mist Village is one of the top 5 greatest Shinobi countries. The village's Kage carries the title of Mizukage. Being located in the land of Water, all of their jutsus are based on water techniques. Not much more is known about this village. Although it was commonly referred to by other villages as 'Bloody Mist Village' for its rumored brutality.
This is also the village where Zabuza and Haku originated from before they abandoned the land. The training customs of the village were revealed from Zabuza's childhood. The final exam to becoming a genin was different, and much more brutal, from the exam the students in Leaf Village had to take. The Hidden Mist was also the home of the famous Kaguya clan, a clan with Kimimaro Kaguya as its soul survivor.
In order for a Ninja Academy student to graduate and become a Genin in the Hidden Mist Village, he or she had to fight, with one of the same friends they trained with, to the death. But all of this had to be changed 10 years ago when one of that year's students, who failed to pass the preliminary exam, went beserk and killed over 100 peers without hesitation. This child was called Momochi Zabuza. After the incident they changed the final exam for the graduating class. In chapter 303 Yamato states that Sai was also subjected to this method of training in preparation to serve under Danzo's Root division.
The strongest and most famous ninjas of the hidden Mist, are known as the Seven Swordsmen of the Mist. All of its members wield a unique weapon. Momochi Zabuza, Hoshigaki Kisame and Raiga Kurosuki are the only known members at this time. Out of those three only Kisame is still alive at the moment. The identities of the other four are still unknown.