Duel is a fair and square battle between two users from same Kingdom.
Right click with the mouse on the opponent to request for a duel. Upon the acceptance from the opponent, 10 seconds of countdown starts.
There are no rewards or penalty from a duel. Think of it as a combat experience.

Rules and Regulations

Victory : There is a 4 minutes of time limit and the one defeats the other is the winner.
             If the opponent leaves the duel zone and does not return within 7 seconds,
             the one remaining in the area is the winner.

Draw : If no one defeats the other within the time limit, it's a tie game.
           Also, if any external pressure occurs from the characters other than the ones fighting,
           the duel ends as tie game.

Note that the HP and MP that were lost during the duel needs time to recover. However, all the magical effects on the characters from the duel will disappear.