Tenzen Daikoku

was a crime boss who lost many men to the blade of Zabuza Momochi during the latter's attempted coup d'etat of Kirigakure.

Background
Looking for revenge years later, he sought out Zabuza Momochi to capture him, but when he discovered that Zabuza was dead he instead plundered Zabuza's blade from his grave in the Land of Waves. He was an aide to the daimyo of the Land of Water and a politician.

Hunt for Itachi arc
After being warned by Sasuke Uchiha (under the impression that Sasuke is, in fact, Suigetsu Hōzuki), he sends out his men to fight Suigetsu, who he believed was coming to take the blade of Zabuza Momochi. Suigetsu defeats the men and enters Tenzen's room, asking for Zabuza's sword. Tenzen's bodyguard attacks Suigetsu with the sword in question. As the guard takes a swing at Suigetsu he misses, as Suigetsu simply uses the Hydration Technique to reform, and in moments the bodyguard is defeated. Sasuke enters the room and Tenzen tries to blame Sasuke for Zabuza's death. Suigetsu explains that he doesn't care and takes the sword, and leaves the place with Sasuke, but not before chopping the pillars in the room with the blade, making it collapse, thus destroying the castle. His fate is unknown, but it's most likely that he's dead.

Trivia

 * Daikoku has a lot of power in both the political and criminal worlds, and was shown to be feared by regular people.
 * He had control of even more men than Gatō had, and even had control of his bodyguards.

Quotes

 * (To Sasuke) "Y-you're the one from yesterday!"
 * (To Suigetsu) "Sasuke Uchiha?! You mean the one that killed Orochimaru?!"