Where To Find: Near Loreius Farm, Must Complete the Dark Brotherhood Quest Line and Spare His Life
Specialization: Sneak

You'll first run into Cicero near Loreius Farm, north of Whiterun, with a broken wagon and a few problems of his own. You can choose to help him fix his wagon or report him to the authorities for being suspicious. Why a guy with a broken down wagon is suspicious doesn't really make sense to me, but he is wearing a jester outfit. Maybe that's against the law? Skyrim's war on laughter is getting out of hand if this is true.

Later on, SPOILER ALERT, you'll meet Cicero when running through the Dark Brotherhood quest line, where players will be given the option to kill Cicero or let him live. If you let the Keeper of the Dark Brotherhood live, you will be given the option to take him on as your companion. He has skills similar to those of the Dark Brotherhood initiates and can sneak around with the best of them. Plus, that jester outfit is just boss.