Chuft Captain used a Slaver stasis box to divert the shuttle manned by Spock, Sulu and Uhura of the starship USS Enterprise. That way he could open another Slaver box in which he did find a powerful weapon.
The Kzin was eager to taste Human meat, something his species was not able to do since the defeat in the Earth-Kzin Wars. However he could not achieve his goal, because he was killed by the weapon's self-destruct function found in the Slaver box. (TAS: "The Slaver Weapon")
The voice of Chuft Captain was provided by James Doohan. His rank is part of his name per Kzinti naming conventions used in the episode, which, while not explicitly discussed, correspond to those used by the species' creator, Larry Niven in his various stories of the "Known Universe."