A PvP duel, or just a duel is when two or more players engage in combat in an unstructured scenario. For structured, rule and wager based duels, see PvP leagues .

To request a duel with another player, the first player must be transformed as a monster, and must initiate an attack against the second player. If the player responds by transforming themselves, they have accepted the challenge, and combat will begin. If they are already transformed, they must return fire if they wish to accept the challenge. If the second player does not wish to accept the duel, they may simply ignore the first player's aggressions without consequence. If the challenge is not returned in 10 seconds, the challenge expires and must be resent.

In the event of duels between parties, the party leaders must accept/initiate the challenge invitation.

A player may challenge multiple players or parties to a duel in the same manner that they issue a single challenge. In this instance, each player or party who accepts will be part of a free for all; however, the match will not begin until all challenges expire.

The duel ends when all but one player/party run out of useable monsters or when all but one player/party have issued a forfeit from the on-screen dialogue. Stab is useable, but is somewhat ineffective unless an opposing player is caught off guard. All defeated players will white out and respawn a short distance from the duel's location. Their monsters' stats will remain the same as in the duel, so if they were defeated by having no useable monsters, they will have to return to a restoration center before. If they forfeited, their monsters will remain in the state that they were in when the player forfeited.