Underdog. Someone who enters a competition supposedly just as a filler, someone without any hopes of making it beyond the opening round. Wikipedia says an underdog is a person or group in a competition, frequently in electoral politics, sports, and creative works, who is popularly expected to lose. Yes that's what an underdog is - a supposed no hoper.
There are times though when the underdog decides to snatch away some of the limelight from his more illustrious counterparts, leaving behind utter shock and surprise and awe in his wake. It's at these times that they realise how much they underestimated that underdog. The victory is never seen coming. It takes on everyone by surprise. Everyone, but the underdog. He always believed he would win some day. He never lost hope, ever so perseverant, no matter how hostile his status quo may seem. He always respected his failures, learning more from them than the joy that he derives from his victories.
There are occasions though, when the underdog has an added onus of taking his one off win forward towards reaching the pinnacle. He has to some how sustain his confidence and his will power to take him that one step forward, where lady luck may not always be at his side. It's time for him to humble the champions. He knows he has had a bit of good fortune in getting to where he is now. Few are such chances that he gets, rather this may be the only chance he'll ever get, and it is upon him to make this a memorable moment for him to cherish forever.
And so the underdog decides to fight on. He has nothing to lose anyway. Rather there's an incentive here to enjoy the war, the competition. The result of defeat shall be no different from what his situation is now - he'll still be the underdog. But victory will bring a respect, an admiration, a sense of wonder from his contemporaries, hitherto unimaginable. His little known skills make him an intimidating adversary. He knows he doesn't have what it takes to be a champion. But he damn well knows how to create an upset.
Behold the underdog.