Short answers, pulled from the story.
The word Marshal traces its roots back to the Carolingians from the ancient German word marascahl, which described a stable supervisor who took care of the king's horses. This role acquired prestige during the early Middle Age as battle horses became more important and eventually evolved into the title Marshal of France.
A decree of the 21st of February 1793 abolished the dignity of Marshal altogether following a law of the 4th of March 1791 that had reduced their number to six. The position remained active until this abolition before Napoleon Bonaparte reestablished it eleven years later as part of his new Empire.
A Marshal displayed four silvered stars while the top military rank of the time known as General of Division displayed three stars. Contrary to most paintings of the time these four stars were silvered rather than gilded according to historical records.
Three Marshals including Jean Lannes, Jean-Baptiste Bessières and Józef Poniatowski were killed in action or died as a result of battle wounds during the Napoleonic Wars. These officers often exposed themselves to great dangers on European battlefields despite not being normally expected to lead from the front.
Two Marshals Joachim Murat and Jean-Baptiste Bernadotte went on to become kings with the latter being the direct ancestor of the current Swedish royal family. This transition occurred among men who held significant commands during the French Revolutionary Wars and received promotions for their military accomplishments.