User blog comment:BenRG/New Teaser Pic From Monty/@comment-7387716-20140324142647

Probably a course about protecting yourself in tight spots without your usual weapons to keep Grimm and other enemies away from you. Or possibly be an improv battle between Weiss at some sort of emergency in Beacon and didn't brought her weapon that day because of reasons.

Or like what someone commented below, the sword being a standhold for an upgraded Myrtenaster, which would be spoilerific if shown at this point of time.