I think that a good character has a unique or unusual trait that makes them memorable. There are hundreds of fighters and sell-swords, but only one fighter who quotes Trollish poetry as he stabs you in the throat. There are many superheroes who use magic, but how many are humans who accidentally trapped themselves into the body of a monkey? In my opinion, to make your character stand out give them a mannerism or quirk that will have people talking about them.