A mercenary is loyal as long as he is paid well, Carthage had a shortage of metal at the end of the first punic war and it ended with the mercenary war, lasting for four years.

Hannibal was a very imposing figure. He held his troops together with a bit of a Machiavellian duality. Though there were some deserters during his march through the Alps, Hannibal's family name, powerful personality, military might and victories and his battlefield genius were enough to reign in dissenters. Also, he led his army through the Alps from the rear atop his largest war elephant so he could keep watch for any deserters.