An extremely big lie. No, I'm serious—this one is beyond whopper-sized. 'Glory,' aka 'honour,' is a weird, sadistic system of points awarded by the Watcher depending on how close a contestant comes to dying during a fight without actually dying—the closer to death, the more glory.1) So glory and honour are just another way of counting up all the times you almost got your ass kicked but didn't. There's nothing glorious or honourable about that. And being fickle, the Watcher resets your score to 0 at the beginning of each new day.
The best and strongest fighters all have low glory rankings, since they dispatch their opponents quickly and without giving their opponents a chance to nearly kill them. You are hereby advised to avoid glory and honour at all costs. We mean it—you have been warned.
At this time, according to the scientists at Improbable Central, glory doesn't do anything except give you bragging rights, assuming you have a lot of glory.