Duel is a feature that allows a player to challenge another player to a basic PvP activity.
To initiate a duel, target a player and type a
/duel command in an in-game chat. The challenged player has to accept the duel request.
Duels were firstly introduced in a pre CBT2 progress report post.
The project Ymirheim developers' comment regarding the current state of the newly implemented feature:
"For now, the duel implementation is very basic: there is no win condition, no restrictions… It just lets two players to fight each other. Everything else is up to you."