Edward Mars, as his name suggest, is an alien. In fact, he is the only alien to be feature on lost.
Before coming to the Island, Edward Mars tried to start a chocolate bar company called "Mars Bars". However, after being sued by Mars Inc., he gave up the dream and became a US Marshall instead.
In flashbacks, it was revealed that Mars had the hots for Kate, whom he was chasing after she killed her dad and ran from the law. Like many men, he often fantasized about Kate in handcuffs. Unlike many men, his fantasy involved him capturing Kate, handcuffing her and taking her on a airplane ride, which would ultimatley crash and leave Mars and handcuffed Kate all alone on an uninhabited Island where he could have his way with her. Even worse was that Mars took his weird fantasy a little too far and attempted to make it a reality, thus breaking the fantasy/creepo barrier.
Edward Mars captuerd Kate and got on a plane. It seemed like things were going well. However, being dubbed a creepo with no significant backstory, Mars was hit in the head by a suitcase, impaled by sharpel, shot by Sawyer, suffacated on his own blood, and eventually (after the island announced "FINISH HIM"), shot and killed by Jack.
Edward Mars died a lonely, lonely man - no closer to fulfilling his creepy fantasies about Kate.
- Edward Mars' rival, Johnny Apollo, was more successful in his candy bar aspirations.
- The only other characters known to break the fantasy/creepo barrier were Locke and Desmond (who both tied Kate up in the Swan) and Alex (who fondled Kate while she was tied up at Pala Ferry). However, since Alex was a hot girl herself the fantasy/creepo barrier does not apply.