How Do You Tackle A Female Colleague At Work Who's Trying To Control You?

This colleague of mine is not my boss, we're on same level, but since she reports directly to my boss? She's always concocting stories in her favor which is putting me in the line of fire, she has gradually given herself the title mouthpiece of the boss, I'm enjoying the job but she makes sure I'm always frustrated and thinking of quitting because of her, i don't want to report her, who knows, my boss might take her side and I'd be doomed