Demonic or whatever voice to skull bs have in common one thing:

"voice" always speak about You
about other people
about things, matters, about the world,
countless examples but from one perspective

to get rid of it Start talking about yourself in your mind!

If You can't find honest or even any words to describe yourself it is not manner of humility but lack of will.

"Will can move mountains"

Start declaring who You believe You are
What You are doing
What do You want

Regain your free will starting from your own head.