Also, CoS can it be Geomancied?
My thoughts were. Have is as the "striker" which as his after charge, before attack action chuck CoS on the unit he has surprised. This would A) remove it from your own unit. B) debuff his targets.
The warden could then hold them up while the blockers move into help mop up.
Of course, I am a slight novice with this, so my theory-fu could be devastatingly wrong.