Alboos has posted a new developer blog for Mythos today explaining the Dueling system. To duel in Mythos, a player will need to issue a challenge and when it's accepted, the two players will be moved to a battlefield where they can fight it out without outside player interference. However, the duels will take place in an area that has low level monsters, so players might be using these creatures to help with the battle. Luckily, when players are killed in a duel they can resurrect right away and continue dueling the other player or exit the duel to carry on with their adventure.

You can read more here.