Silver Linings (Cast Aside)

I am the elimination of threats.
I am the one you seek in self defense.
The brass-knuckled friend.
The violence in the end.
I am folded arms and rolled shoulders,
I am the wall you can't knock over.
The oft-broken nose.
The thorns adorning a rose.
I am accompanied by awkward silence.
I am acknowledged only when there's required violence.
The bottled up rage.
The things better left contained.