×Wraithwings that do not want to come to you will be encouraged to do so if you stand in proximity to another (<5 squares). Try to kill as many wraithwings as fast as you can - if one is near to you, stand near to another to lure it towards you before advancing. You may find the wraithwings in the central closed areas useful for this (especially if there are only a few monsters left), since they cannot run away.