Use Command see who in Duel Room

[Rexter]

My suggestion to command duel room,
make to provide the key to find out who in the midst of fighting in the duel room like
/listduel and the list is in the duel room will open, like a Room.1 ABC and DEF / Room.2 ( empty ).

[Alcander]

Why would you need that when you have Titus with whom when you talk it will show you exactly what you suggested ?.
See the guide here MuGuides