Rick or Richard Blaine, if you prefer, is a man who has led a 'chequered' and 'colourful' life.  He left America for reasons unknown, and also at one time, ran guns into Ethiopia and fought for the losing side in the Spanish Civil War. He now, by his own admission, is running a saloon in Casablanca.
By contrast his friend, Capt. Louis Renault, describes himself as a pragmatic realist. He blows with the prevailing wind, which in this case, is the Vichy French government which collaborated with the Germans following France's defeat in 1940. In addition to collaborating, Capt. Renault is also an opportunist, an extortionist, a gambler and a 'hedonist' always ready to take advantage of any attractive female that crosses his path. Expertly played in the film by noted British character actor, Claude Raines, he is the perfect foil to Rick Blaine.