Origin

Morn is a regular at Quark's.  He is known for being really talkative.  He is at the bar so much that he even has his own stool.  The stool was almost made into a shrine when it was thought he was dead.  He had an odd look but people like Jadzia Dax found him attractive.

Creation

The producers of the Star Trek: Deep Space Nine television show created the character of Morn because they wanted to have a regular at Quark's Bar.  They never intended for him to have a role they just wanted him to always be around.  his name was modeled after the famous Barfly from the television show Cheers, Norm.  They just switched the letters N and m from Norm and made him Morn.