What we call "demons" (there is more to this subject but in this piece I am capturing it in just psychological sense and how it ties in with the human mind) are our saṃskāra (impressions/imprints cyclically creating and shaping themselves/tendencies) which we have long confused to be the (true) Self/That.
Anything that triggers us and brings us face to face with them is doing the work of the Gurū showing us the way to our limitless untouched true nature/That.
Each trigger and the associated reactivity holds the key to realisation and liberation. Each unconscious reaction can reinforce the existing bondage by way of strengthening the accumulation of existing tendencies and the identification to them owing to the identification with them.
The sākṣi (witness-awareness/total presence) is the quiet lamp guiding us out of the deceptions of the mind until the following happens 
"gate gate pāragate pārasaṃgate bodhi svāhā" (translates to gone gone completely to the other shore, which is to say the empty substanceless seemingly arising a.k.a. nature of mind and therefore everything it projects is seen/realised to be just as substance-less because you see they are not two at which point one truly starts living from the being than being swayed by the influences-perceptions of the mind.. 
Naturally this deepens and settles with continual proper practice.
All perceived images/things/objects lose influence when we are just present a.k.a. fully seeing. fully feeling. fully tasting. fully hearing and listening. 
Choicelessly. a.k.a. being available/receptive to ever-present grace.
And when all experienching/perceiving quiets down owing to presence what then remains is just the You/That.
Continual surrender feeding realisation.)