Facing your inner demon.

could be a realization like thunder bow said.. or if you have been long trying to escape/ battle outside negativity... maybe feeling that you are trapped in a defensive loop that is wearing you down to the point where you either fear that they are right or feeling it might just be easier to give in to thes doubts or opinions and allow then ( worst you) to slay ( true you)..then to keep on fighting.
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"The woods are lovely, dark, and deep
But I have promises to keep
And miles to go before I sleep
And miles to go before I sleep"