He is a veteran of the NCR, currently holding the rank of Major. He was also at Bitter Springs, and was a captain at the time. He's currently in charge of NCR Ranger troops at Camp McCarran. He's the adoptive father of Sgt. Bitter-Root. He has a strong disgust for the Fiends and the Great Khans. He's currently in charge of the bounties at Camp McCarran and will pay handsomely for the heads of three specific Fiends. 
Three-Card Bounty: Dhatri wants bounty hunters to kill three Fiend leaders and take their heads to him, for which he will pay a handsome reward, but he's very particular about the means of their deaths - no headshots or decapitations which might disfigure the gruesome trophies. 
"Yeah, I was there. I was Captain Dhatri, then. That whole situation was a mess and could easily have been avoided with good intel. The major in charge at the time made a bad call - he thought Bitter Springs was full of Great Khan raiders, so we surrounded the place. By the time any of us realized there were civilians down there - women and children - the shooting had already started. The major froze up at the news, and we couldn't get another word out of him. I took over and salvaged the situation as best I could. For my effort, I was promoted to major. Not quite the way I'd have wanted it."
pc After killing Driver Nephi in "Three-Card Bounty" Major Dhatri may be dead upon returning to Camp McCarran making the quest unable to be completed. It appears Dhatri may have taken friendly fire bullets and died near the firing range. [verified]
xbox360 After killing Caesar and his legionaries at The Fort if you then fast travel to Camp McCarran Dhatri may show up as an enemy on the compass, causing your companions to shoot at him. [verified]
ps3pcxbox360 Sometimes Dhatri is nowhere to be found and may be glitched out of the world. Use player.placeatme 000f56f8 console command, Mayor will spawn on your head, and you may complete the quest.[verified]