Right click on the opponent to request for a duel. Upon the acceptance, the battle will be initiated after 10 seconds.
There is no rewards or penalties. You can enjoy the battle with getting combat experience through requesting a duel.

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.