Do'Shaar was a monk of the whispering fang cult but as Mi'Aiq has said, after Kahjiit arrive in Skyrim something strange happens to them.    While wandering the wilds of high rock he went native and started worshiping the old gods.

Recently he became convinced that it's his duty to follow the Dragonborn.  Do'Shaar was trained since birth to be an assassin, He's almost undetectable when sneaking. A highly skilled unarmed fighter who fights silently.

If you build up your own sneak skills you'll find he's extremely efficient at eliminating any lone advisory.   Work your way behind them then order Do'Shaar to attack.  If he can he'll quietly dispatch his target without raising any alarms.

Do'Shaar requires nothing more than Skyrim with the official update.  Images show Do'Shaar with these mods (I think)  Muscular Khajiit Textures http://www.nexusmods.com/skyrim /mods/40043/  and  Bulky Skeleton for Beast Race http://www.nexusmods.com/skyrim/mods/61132/

You'll find Do'Sharr in the Markarth Warrens.