71-hour Ahmed (called "72-hour Achmed" in The Art of Discworld and sometimes misspelled 71-hour Achmed) is the wali or head policeman in Klatch. He is of D'reg origin and was trained as an assassin in Ankh-Morpork where he was a member of Viper House. He endeavors to be a little bit foreign wherever he goes which lets him perform his duties with fewer complications.
He takes his name for the fact that he did not follow custom and tradition which play a vital role in Klatchian culture when assassinating an man who had killed a whole village. The proper etiquette is to give hospitatlity to even your worst enemy for no less than three days in your home. When Ahmed was visited by the man, he did not wait the full three days (seventy-two hours) to cut off his head knowing that the other man would have kill Ahmed once the time for hospitality had passed. This gross breach of etiquette earned him his feared nickname.
His only appearance is in Jingo, where he accompanies Prince Khufurah from Klatch on a visit to Ank-Morpork. He and commander Vimes become entangled in the political problems that follow the surfacing of the island Leshp, both trying to find the person who tried to kill the prince, and both suspicious of their own side. Ahmed, who plays the role of a dumb foreigner, is in fact very intelligent and, like Vimes, a natural policeman. He disappears into the desert to finish his job by the end of the novel.
There are many parallels between 71-hour Ahmed and Vimes in this novel and in Vimes' actions in later ones. Like 71-hour Achmed mission in Ankh-Morpork in Jingo, in Monstrous Regiment and The Fifth Elephant, Vimes is sent to a foreign country on an ostensibly diplomatic mission with a goal of deliberately stirring the muddy waters to see what emerges. Perhaps Vetinari decided take a page out of 71-hour Ahmed's book in sending Vimes on these assignment; sending someone who appears to be a bit of a bumpkin to stir things up and create an advantage for Ankh-Morpork.
The Art of Discworld